Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · March 1, 2023
Neutron detectors used in various applications in nuclear security and nuclear safety are mostly based on the 3He technology. Unfortunately, in the last few years, the market of 3He has encountered huge problems in matching the supply ...
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Journal articleIEEE Transactions on Parallel and Distributed Systems · June 1, 2021
Within scientific infrastructuscientists execute millions of computational jobs daily, resulting in the movement of petabytes of data over the heterogeneous infrastructure. Monitoring the computing and user activities over such a complex infrastructure is ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · April 1, 2020
Ionising radiation detectors based on wide band-gap materials have the potential to operate at temperatures higher than 200°C. Such detectors are important in applications such as monitoring near nuclear reactors and in deep oil and gas well borehole loggi ...
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Journal articlePlasma Physics and Controlled Fusion · October 15, 2019
A new extensive validation study performed for a modest-beta National Spherical Torus eXperiment (NSTX) neutral beam injection-heated H-mode discharge predicts that electron thermal transport can be entirely explained by short-wavelength electron-scale tur ...
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Journal articleNuclear Fusion · August 6, 2019
Electron-scale turbulence (for 3 k s12) was measured during the L-H transition in the National Spherical Torus Experiment (NSTX) (Ono et al 2000 Nucl. Fusion 40 557) using a coherent microwave scattering system. The measurements were carried out at a radia ...
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Journal articleNuclear Fusion · June 5, 2019
The mission of the spherical tokamak NSTX-U is to explore the physics that drives core and pedestal transport and stability at high-β and low collisionality, as part of the development of the spherical tokamak (ST) concept towards a compact, low-cost ST-ba ...
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Journal articleAdvanced Optical Materials · May 3, 2019
Mapping strain fields in visually opaque structural composites—for which failure is often sudden, irreparable, and even catastrophic—requires techniques to locate and record regions of stress, fatigue, and incipient failure. Many composite materials are tr ...
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Journal articleOptics express · March 2019
A fundamental challenge has plagued computer-generated volumetric holography since its inception: design methods are available only in the perturbative limit, but this poses serious limitations on efficiency and the amount of multiplexing achievable. Given ...
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Journal articleRemote Sensing · March 1, 2019
The correlation-based synthetic aperture radar imaging technique, termed radar coincidence imaging, is extended to a fully multistatic multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) configuration. Within this framework, we explore two ...
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Journal articleOptica · February 20, 2019
Multicolor waveguide holography remains a challenge due to its inherent design complexity, compounded by the limited low-loss materials available in the optical range as well as challenges in nanofabrication. In this study, we first propose and experimenta ...
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Journal articleIEEE Transactions on Communications · February 1, 2019
We propose a spatial multiplexing system using reconfigurable cavity-backed metasurface antennas. The metasurface antennas consist of a printed cavity with dynamically tunable metamaterial radiators patterned on one side and fed by multiple radio frequency ...
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Journal articleOptica · December 20, 2018
Phase information and spatially coherent illumination have usually been considered indispensable components of most microwave imaging systems. Dynamic metasurface apertures (DMAs)—with their ability to generate spatially incoherent illumination—have recent ...
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Journal articleIet Radar Sonar and Navigation · November 1, 2018
Synthetic aperture radar (SAR) imaging with an independently moving transmitter and receiver introduces motion artefacts difficult to compensate for, especially between satellites in separate orbits that rendezvous over a target. A solution for polarisatio ...
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Journal articleThe Review of scientific instruments · October 2018
The 2D turbulent E × B flow-field is inferred from density fluctuation images obtained with the beam emission spectroscopy diagnostic on DIII-D using the orthogonal dynamic programming velocimetry algorithm. A synthetic turbulence model is us ...
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Journal articlePhysical review letters · August 2018
Complicated multipath trajectories of waves in disordered cavities cause object localization to be very challenging with traditional ray-tracing approaches. Yet it is known that information about the object position is encoded in the Green's function. Afte ...
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Journal articleApplied optics · May 2018
Through aperture synthesis, an electrically small antenna can be used to form a high-resolution imaging system capable of reconstructing three-dimensional (3D) scenes. However, the large spectral bandwidth typically required in synthetic aperture radar sys ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · April 2018
Multiplex volume holograms are conventionally constructed by the repeated exposure of a photosensitive medium to a sequence of external fields, each field typically being the superposition of a reference wave that reconstructs the hologram and the other be ...
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Journal articleScientific reports · April 2018
Detecting and analysing motion is a key feature of Smart Homes and the connected sensor vision they embrace. At present, most motion sensors operate in line-of-sight Doppler shift schemes. Here, we propose an alternative approach suitable for indoor enviro ...
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Journal articleIEEE Access · March 14, 2018
We demonstrate a computational, frequency-diverse, phaseless imaging technique at microwave frequencies that minimizes the impacts of phase calibration and alignment errors on image reconstruction. Phase calibration error is introduced by means of misalign ...
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Journal articleOptics Communications · March 1, 2018
A patterned, plasmonic metasurface can strongly scatter incident light, functioning as an extremely low-profile lens, filter, reflector or other optical device. When the metasurface is patterned uniformly, its linear optical properties can be expressed usi ...
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Journal articleOptics express · March 2018
The weak scattering approximation is used when designing optical media that couple fields together, but to account for the interactions of multiple fields in a volume or to achieve the best efficiency, the solution must be consistent with Maxwell's equatio ...
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Journal articleApplied optics · March 2018
We demonstrate a dynamic metasurface aperture as a unique tool for computational ghost imaging at microwave frequencies. The aperture consists of a microstrip waveguide loaded with an array of metamaterial elements, each of which couples energy from the wa ...
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Journal articleOptics express · March 2018
We present a reconfigurable, dynamic beam steering holographic metasurface aperture to synthesize a microwave camera at K-band frequencies. The aperture consists of a 1D printed microstrip transmission line with the front surface patterned into an array of ...
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Journal articleIEEE Access · February 2, 2018
We present the design and experimental demonstration of a cavity-backed, holographic metasurface capable of focusing microwaves in the Fresnel zone. The circular cavity consists of two stacked plates: microwaves are injected into the bottom plate via a coa ...
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Journal articleOptics express · February 2018
We study the angle-dependent optical reflectance spectrum of a metasurface consisting of a periodic array of film-coupled plasmonic nanopatch particles. The nanopatch metasurface exhibits a strong, angle-independent absorption resonance at a wavelength def ...
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Journal articleIEEE Transactions on Microwave Theory and Techniques · January 1, 2018
We present a modulated ultrawideband backscatter calibration target (fiducial) intended for group delay calibration in large-aperture multitransceiver millimeter-wave imagers. The fiducial is designed to resemble a modulated point scatterer across the K-ba ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · January 2018
The radiating mode of a cavity antenna at a particular frequency is fixed. However, by actively modulating the permittivity inside the cavity, the radiating mode may be changed. Using time-independent perturbation theory, we derive the modes of a cavity pe ...
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Journal articleApplied optics · January 2018
We demonstrate a computer-generated metasurface hologram in which four distinct images are encoded at four different W-band (75-110 GHz) frequencies. The metasurface hologram consists of a planar array of resonant metamaterial elements excited by a collima ...
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Journal articleProgress in Electromagnetics Research C · January 1, 2018
A new structure design of a dual-band suspended microstrip meshed patch antenna integrated with a polycrystalline silicon solar cell for Ku-band satellite applications is proposed and presented. This antenna element is a basic building block for a Ku-band ...
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Journal articleLight, science & applications · January 2018
During the past decades, major advances have been made in both the generation and detection of infrared light; however, its efficient wavefront manipulation and information processing still encounter great challenges. Efficient and fast optoelectronic modu ...
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Journal articleIEEE Access · January 1, 2018
We experimentally demonstrate a frequency-diverse, computational imaging system at W-band frequencies utilizing an array of cavity-fed metasurface antennas. Each metasurface antenna consists of a cavity milled from aluminum stock, with an upper plate patte ...
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Journal articleOptica · December 20, 2017
When imaging through layered media such as walls, the contents and thickness of the wall layers are generally not known a priori. Furthermore, compensating for their effects can be computationally intensive, as this generally requires modelling the transmi ...
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Journal articlePhysical Review B · December 4, 2017
We consider the design and modeling of metasurfaces that couple energy from guided waves to propagating wave fronts. To this purpose, we develop a comprehensive, multiscale dipolar interpretation for large arrays of complementary metamaterial elements embe ...
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Journal articleIEEE Transactions on Antennas and Propagation · December 1, 2017
We investigate the use of a dynamic metasurface as the transmitting antenna for a synthetic aperture radar (SAR) imaging system. The dynamic metasurface consists of a 1-D microstrip waveguide with complementary electric resonator (cELC) elements patterned ...
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Journal articleJournal of the Optical Society of America B Optical Physics · December 1, 2017
Waveguide-fed dynamic metasurface antennas (DMAs) can be used in a variety of synthetic aperture radar (SAR) modalities for microwave and millimeter-wave imaging. The DMA consists of an electrically large array of resonant, dynamically reconfigurable metam ...
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Journal articlePhysical Review Applied · November 29, 2017
The metasurface concept has emerged as an advantageous reconfigurable antenna architecture for beam forming and wave-front shaping, with applications that include satellite and terrestrial communications, radar, imaging, and wireless power transfer. The me ...
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Journal articleIet Radar Sonar and Navigation · November 1, 2017
There exist few rapid reconstruction methods for applications that use multistatic radar for targets in the near field such as vehicle navigation and personnel screening. Fourier accelerated multistatic imaging (FAMI) is a method that combines the rapid re ...
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Journal articleOptics express · October 2017
We propose a polarimetric microwave imaging technique that exploits recent advances in computational imaging. We utilize a frequency-diverse cavity-backed metasurface, allowing us to demonstrate high-resolution polarimetric imaging using a single transceiv ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · August 31, 2017
Phaseless imaging approaches provide a significant advantage for systems where maintaining coherency during the acquisition time is difficult. Here, we demonstrate a phaseless, frequency-diverse, computational imaging system that operates at K-band frequen ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · August 24, 2017
Multibeam antennas have emerged as a promising concept for applications where selective beam coverage is required. Multibeam radiation can be achieved leveraging the concept of metasurfaces, enabling the radiated wavefronts to be tailored in an all-electro ...
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Journal articleJournal of the Optical Society of America B Optical Physics · August 1, 2017
Conventional microwave imaging schemes, enabled by the ubiquity of coherent sources and detectors, have traditionally relied on frequency bandwidth to retrieve range information, while using mechanical or electronic beamsteering to obtain cross-range infor ...
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Journal articleNature communications · July 2017
Optical metamaterials with an artificial subwavelength structure offer new approaches to implement advanced optical devices. However, some of the biggest challenges associated with the development of metamaterials in the visible spectrum are the high costs ...
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Journal articleIEEE Transactions on Geoscience and Remote Sensing · July 1, 2017
To maintain sufficient signal-To-noise ratio (SNR) for image reconstruction and image interpretation, conventional synthetic aperture radar (SAR) systems must trade off resolution and scene size. This paper proposes a new SAR mode of operation, which impro ...
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Journal articleOptics express · July 2017
Computational imaging systems leverage generalized measurements to produce high-fidelity images, enabling novel and often lower cost hardware platforms at the expense of increased processing. However, obtaining full resolution images across a large field-o ...
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Journal articleNuclear Fusion · June 20, 2017
The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in the summer of 2015. NSTX-U first plasma was subsequently achieved, diagnostic and control systems have been commissioned, t ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · May 2017
We investigate the application of dynamic metasurface antennas (DMAs) to synthetic aperture radar (SAR) systems. Metasurface antennas can generate a multitude of tailored electromagnetic waveforms from a physical platform that is low-cost, lightweight, and ...
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Journal articleOptics express · May 2017
We present a rigorous derivation of the weak-form formulation of the Helmholtz equation for electromagnetic structures incorporating general nonreciprocal, dispersive materials such as magnetized ferrites or magnetized free-carrier plasmas. This formulatio ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · April 2017
Frequency diversity antennas with spatially structured radiation patterns reduce the reliance on actively switched elements for beamforming which become increasingly expensive and impractical as frequency increases. As the quality factor Q of a frequency d ...
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Journal articlePhysical Review A · March 20, 2017
We compute the reflectance properties of a metasurface that consists of a doubly periodic array of patch nanoantennas strongly coupled to a metallic film. Each plasmonic patch antenna can be accurately modeled as a polarizable, radiating, magnetic dipole. ...
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Journal articleNuclear Fusion · March 10, 2017
The anomalous level of electron thermal transport inferred in magnetically confined configurations is one of the most challenging problems for the ultimate realization of fusion power using toroidal devices: tokamaks, spherical tori and stellarators. It is ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · February 11, 2017
Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and ...
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Journal articleAdvanced materials (Deerfield Beach, Fla.) · February 2017
Multispectral colloidal metasurfaces are fabricated that exhibit greater than 85% absorption and ≈100 nm linewidths by patterning film-coupled nanocubes in pixels using a fusion of bottom-up and top-down fabrication techniques over wafer-scale areas. With ...
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Journal articleScientific reports · February 2017
We demonstrate a low-profile holographic imaging system at millimeter wavelengths based on an aperture composed of frequency-diverse metasurfaces. Utilizing measurements of spatially-diverse field patterns, diffraction-limited images of human-sized subject ...
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Journal articleJournal of the Optical Society of America B Optical Physics · February 1, 2017
Synthetic aperture radar (SAR) synthesizes a large effective aperture via coherent processing of multiple measurements taken from a moving platform. We present an approach for SAR imaging using an X-band (10-13.7 GHz) dynamic metasurface antenna (MSA). Thi ...
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Journal articleJournal of Instrumentation · January 23, 2017
Single crystal CVD diamond has many desirable properties as a radiation detector; exceptional radiation hardness and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry and transmission mode applications), wide bandgap ( ...
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Journal articleJournal of Applied Physics · January 7, 2017
Wireless power transfer (WPT) has been an active topic of research, with a number of WPT schemes implemented in the near-field (coupling) and far-field (radiation) regimes. Here, we consider a beamed WPT scheme based on a dynamically reconfigurable source ...
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Journal articleIEEE Access · January 1, 2017
Multiple-input-multiple-output (MIMO) radar image processing presents problems difficult to address by modifying conventional monostatic radar methods as Fourier range migration. When the distance between the transmitter and receiver is comparable to the t ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · January 1, 2017
We present a novel method of rapid prototyping waveguide and antenna using plating on plastic technique. The part is created by high-precision three-dimensional printing and plated with copper using both electroless plating and electroplating. The performa ...
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Journal articleIEEE Transactions on Antennas and Propagation · January 1, 2017
Computational imaging at microwave frequencies has gained traction due to its potential for obtaining high-quality images with fast acquisition rates. Complex and diverse radiation patterns form the cornerstone of this approach. Electrically large antennas ...
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Journal articleIEEE Access · January 1, 2017
We design and numerically analyze a coherent computational imaging system that utilizes a sparse detector array of planar, frequency-diverse, metasurface antennas designed to operate over the W-band frequency range (75-110 GHz). Each of the metasurface ant ...
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Journal articleIEEE Access · January 1, 2017
We present numerical simulations of the near-field focusing capabilities of a dynamically reconfigurable holographic metasurface aperture. The aperture consists of a parallel-plate waveguide in which the upper plate is patterned with a number of metamateri ...
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Journal articleInternational Journal of RF and Microwave Computer Aided Engineering · January 1, 2017
The hemispherical lens antenna is a candidate for satellite communications-on-the-move, offering good scan performance in a reduced height. A short focal length minimizes height but presents challenges in illuminating the lens. Aperture efficiency is domin ...
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Journal articlePhysical Review A · December 7, 2016
We develop an approach to enable the full-wave simulation of stimulated Brillouin scattering and related phenomena in a frequency-domain, finite-element environment. The method uses transformation-optics techniques to implement a time-harmonic coordinate t ...
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Journal articleOptics express · December 2016
Here we introduce a phase-shifting digital holography-based method to determine the temperature profile around an irradiated (sub-)micron spherical bead. The method utilizes a Mach-Zehnder interferometer implemented into an open setup microscope. The resul ...
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Journal articleJournal of Big Data · December 1, 2016
In recent years, there has been an increasing amount of data being produced and stored, which is known as Big Data. The social networks, internet of things, scientific experiments and commercial services play a significant role in generating a vast amount ...
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Journal articlePhysical Review Applied · November 29, 2016
We perform microwave imaging using a dynamically reconfigurable aperture based on a tunable disordered cavity. The electrically large cavity is cubic with a spherical deformation and supports a multitude of distinct electromagnetic modes that vary as a fun ...
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Journal articleJournal of Applied Physics · October 14, 2016
We derive simple analytical expressions to model the electromagnetic response of an electrically large printed cavity. The analytical model is then used to develop printed cavities for microwave imaging purposes. The proposed cavity is excited by a cylindr ...
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Journal articleJournal of the Optical Society of America B Optical Physics · October 1, 2016
Dynamic metasurface antennas are planar structures that exhibit remarkable capabilities in controlling electromagnetic wavefronts, advantages that are particularly attractive for microwave imaging. These antennas exhibit strong frequency dispersion and pro ...
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Journal articleIet Microwaves Antennas and Propagation · August 20, 2016
The authors present a multistatic imaging system at microwave frequencies based on arrays of planar cavity sub-apertures, or panels. The cavity imager consists of sets of transmit and receive panels, loaded with radiating irises distributed over the sub-ap ...
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Journal articleOptics express · August 2016
Holographic optics are an essential tool for the control of light, generating highly complex and tailored light field distributions that can represent physical objects or abstract information. Conceptually, a hologram is a region of space in which an arbit ...
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Journal articleJournal of Lightwave Technology · July 15, 2016
The concept of hybrid free space optical/radio frequency (FSO/RF) communications has been considered for the last mile access network applications. The existing schemes mostly use two separate transceiver antennas for outdoor terrestrial links of few kilom ...
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Journal articleOptics express · July 2016
Computational imaging modalities support a simplification of the active architectures required in an imaging system and these approaches have been validated across the electromagnetic spectrum. Recent implementations have utilized pseudo-orthogonal radiati ...
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Journal articlePhysical Review A · June 27, 2016
A metasurface that absorbs waves from all directions of incidence can be achieved if the surface impedance is made to vary as a function of incidence angle in a specific manner. Here we show that a periodic array of planar nanoparticles coupled to a metal ...
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Journal articleJournal of the Optical Society of America B Optical Physics · June 1, 2016
We investigate the imaging capabilities of a one-dimensional, dynamic, metamaterial aperture that operates at the lower part of K-band microwave frequencies (17.5-21.1 GHz). The dynamic aperture consists of a microstrip transmission line with an array of r ...
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Journal articleIEEE Microwave and Wireless Components Letters · May 1, 2016
We demonstrate a frequency-diverse aperture for microwave imaging based on a planar cavity at K-band frequencies (18-26.5 GHz). The structure consists of an array of radiating circular irises patterned into the front surface of a double-sided printed circu ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · May 2016
Radio imaging devices and synthetic aperture radar typically use either mechanical scanning or phased arrays to illuminate a target with spatially varying radiation patterns. Mechanical scanning is unsuitable for many high-speed imaging applications, and p ...
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Journal articleOptics express · April 2016
We demonstrate a frequency diverse, multistatic microwave imaging system based on a set of transmit and receive, radiating, planar cavity apertures. The cavities consist of double-sided, copper-clad circuit boards, with a series of circular radiating irise ...
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Journal articlePlasma Physics and Controlled Fusion · January 28, 2016
We implement unsupervised machine learning techniques to identify characteristic evolution patterns and associated parameter regimes in edge localized mode (ELM) events observed on the National Spherical Torus Experiment. Multi-channel, localized measureme ...
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Journal articlePhysical Review B · January 13, 2016
In the framework of the hydrodynamic model describing the response of electrons in a metal, we show that arrays of very narrow and shallow metallic slits have an optical response that is influenced by the spatial dispersion in metals arising from the repul ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · January 1, 2016
We present the design of a tunable metamaterial element that can serve as the building block for a dynamically reconfigurable aperture. The element - a complimentary electric-LC (cELC) resonator - is patterned into the upper conductor of a microstrip trans ...
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Journal articleIEEE Access · January 1, 2016
We demonstrate a technique for calibrating a frequency-diverse, multistatic, computational imaging system. A frequency-diverse aperture enables an image to be reconstructed primarily from a set of scattered field measurements taken over a band of frequenci ...
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Journal articleIEEE Access · January 1, 2016
We present the design and simulation of a frequency-diverse aperture for imaging of human-size targets at microwave wavelengths. Predominantly relying on a frequency sweep to produce diverse radiation patterns, the frequency-diverse aperture provides a pat ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · January 1, 2016
We present an analysis of a slotted waveguide antenna (SWA) whose directivity has been enhanced by using metamaterial parasitic elements. We apply an adapted form of the discrete dipole approximation (DDA) as a modeling tool and verify the accuracy and ver ...
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Journal articleProgress in Electromagnetics Research B · January 1, 2016
We examine the effect of alignment errors on the performance of a frequency-diverse imaging system composed of metamaterial apertures. In a frequency-diverse imaging system, a sequence of distinct radiation patterns, indexed by frequency, provides measurem ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · January 1, 2016
A scheme for wireless power transfer (WPT) in the radiative near-field (Fresnel) region is presented. The proposed Fresnel WPT scheme is designed to focus microwaves to a diffraction-limited region where a detector can be positioned, achieving reasonably h ...
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Journal articleAdvanced materials (Deerfield Beach, Fla.) · December 2015
An absorptive metasurface based on film-coupled colloidal silver nanocubes is demonstrated. The metasurfaces are fabricated using simple dip-coating methods and can be deposited over large areas and on arbitrarily shaped objects. The surfaces show nearly c ...
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Journal articleOptics letters · December 2015
Metasurfaces comprising arrays of film-coupled, nanopatch antennas are a promising platform for low-energy, all-optical switches. The large field enhancements that can be achieved in the dielectric spacer region between the nanopatch and the metallic subst ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · December 2015
We explore the possibility of controlling the wake and drag of a spherical object independently of each other, using radial distributions of permeability in the Brinkman-Stokes formalism. By discretizing a graded-permeability shell into discrete, macroscop ...
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Journal articlePhysics of Plasmas · December 1, 2015
Theory and experiments have shown that electron temperature gradient (ETG) turbulence on the electron gyro-scale, k⊥ρe ≲ 1, can be responsible for anomalous electron thermal transport in NSTX. Electron scale (high-k) turbulence is dia ...
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Journal articleApplied Physics Letters · November 16, 2015
We present a dynamic metamaterial aperture for use in computational imaging schemes at microwave frequencies. The aperture consists of an array of complementary, resonant metamaterial elements patterned into the upper conductor of a microstrip line. Each m ...
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Journal articleApplied optics · November 2015
Recently, a frequency-diverse, metamaterial-based aperture has been introduced in the context of microwave and millimeter wave imaging. The generic form of the aperture is that of a parallel plate waveguide, in which complementary metamaterial elements pat ...
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Journal articlePhysics of Plasmas · November 1, 2015
In this letter, we report the first observation of the fast response of electron-scale turbulence to auxiliary heating cessation in National Spherical Torus eXperiment [Ono et al., Nucl. Fusion 40, 557 (2000)]. The observation was made in a set of RF-heate ...
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Journal articleScientific reports · August 2015
The control of quasi-static magnetic fields is of considerable interest in applications including the reduction of electromagnetic interference (EMI), wireless power transfer (WPT), and magnetic resonance imaging (MRI). The shielding of static or quasi-sta ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · August 2015
We provide a numerical tool to quantitatively study the impact of nonlocality arising from free electrons in metals on the optical properties of metallo-dielectric multilayers. We found that scattering matrices are particularly well suited to take into acc ...
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Journal articleNature communications · July 2015
Typical emitters such as molecules, quantum dots and semiconductor quantum wells have slow spontaneous emission with lifetimes of 1-10 ns, creating a mismatch with high-speed nanoscale optoelectronic devices such as light-emitting diodes, single-photon sou ...
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Journal articleOptics express · July 2015
The resonance associated with plasmonic nanostructures strongly enhances local optical fields, and can thus dramatically enhance the nonlinear response of the composite structure. However, the origin of the nonlinear signal generated from hybrid nanostruct ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · May 11, 2015
We investigate both theoretically and experimentally the nonlinear propagation of surface-plasmon polaritons (SPP) on a single air/metal interface. Inspired by nonlinear dielectric waveguide theory, we analytically derive a model that describes the nonline ...
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Journal articleApplied Physics Letters · May 11, 2015
We present a 3D computational imaging system based on a mode-mixing cavity at microwave frequencies. The core component of this system is an electrically large rectangular cavity with one corner re-shaped to catalyze mode mixing, often called a Sinai Billi ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · May 8, 2015
Classical nonlocality in conducting nanostructures has been shown to dramatically alter the linear optical response by placing a fundamental limit on the maximum field enhancement that can be achieved. This limit directly extends to all nonlinear processes ...
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Journal articleNano letters · May 2015
Optical cavities with multiple tunable resonances have the potential to provide unique electromagnetic environments at two or more distinct wavelengths--critical for control of optical processes such as nonlinear generation, entangled photon generation, or ...
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Journal articlePhysics of Plasmas · May 1, 2015
Direct measurements of the pedestal recovery during an edge-localized mode cycle provide evidence that quasi-coherent fluctuations (QCFs) play a role in the inter-ELM pedestal dynamics. Using fast Thomson scattering measurements, the pedestal density and t ...
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Journal articlePhysics of Plasmas · May 1, 2015
In this study, the close physical proximity of the Gas Puff Imaging (GPI) and Beam Emission Spectroscopy (BES) diagnostics on the National Spherical torus Experiment (NSTX) is leveraged to directly compare fluctuation measurements, and to study the local e ...
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Journal articleNuclear Fusion · March 27, 2015
The National Spherical Torus Experiment (NSTX) is currently being upgraded to operate at twice the toroidal field and plasma current (up to 1T and 2MA), with a second, more tangentially aimed neutral beam (NB) for current and rotation control, allowing for ...
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Journal articleNano letters · January 2015
We have combined atomic layer lithography and template stripping to produce a new class of substrates for surface-enhanced infrared absorption (SEIRA) spectroscopy. Our structure consists of a buried and U-shaped metal-insulator-metal waveguide whose folde ...
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Journal articleProgress in Electromagnetics Research · January 1, 2015
The resolution of a frequency diverse compressive metamaterial aperture imager is investigated. The aperture consists of a parallel plate waveguide, in which an array of complementary, resonant metamaterial elements is patterned into one of the plates. Mic ...
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Journal articleSpringer Series in Materials Science · January 1, 2015
Nonlinear metamaterials provide a host of interesting phenomena which, like for their linear counterpart, can be described using homogenized, effective properties. Following the convention used in nonlinear optics, the response of nonlinear metamaterials c ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 2015
Plasmonic systems involve interfaces containing metal and dielectric materials. In an effort to investigate the scaling of the nonlinear response of the surface plasmon polariton at a metal/dielectric interface, where the metal and dielectric present optic ...
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Journal articleOptical Materials Express · January 1, 2015
Plasmonic resonances in metallic nanostructures have been shown to drastically enhance local electromagnetic fields, and thereby increase the efficiency of nonlinear optical phenomena, such as second harmonic generation (SHG). While it has been experimenta ...
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Journal articleACS Photonics · November 19, 2014
Because of their ability to strongly localize and enhance optical fields, plasmonic nanostructures have the potential to dramatically amplify the inherent nonlinear response of materials. We illustrate the impact of this plasmonic interaction by investigat ...
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Journal articleNature Photonics · November 5, 2014
To move nanophotonic devices such as lasers and single-photon sources into the practical realm, a challenging list of requirements must be met, including directional emission, room-temperature and broadband operation, high radiative quantum efficiency and ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · November 3, 2014
Planar metallic nanoparticles separated by nanoscale distances from a metal film support unique plasmonic resonances useful for controlling a wide range of photodynamic processes. The fundamental resonance of a film-coupled planar nanoparticle arises from ...
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Journal articleJournal of the Optical Society of America B Optical Physics · November 1, 2014
The local plasmon resonances of metallic nanostructures are commonly associated with massive local field enhancements, capable of increasing the photoexcitation of nearby quantum emitters by orders of magnitude. However, these same plasmonic structures sup ...
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Journal articleApplied Physics Letters · October 2, 2014
Colloidally synthesized nanocubes strongly coupled to conducting films hold great promise for enhancing different nonlinear optical processes. They exhibit a robust and sensitive scattering response that can be easily controlled by their geometrical and ma ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · October 2014
We demonstrate a microwave imaging system that combines advances in metamaterial aperture design with emerging computational imaging techniques. The flexibility inherent to guided-wave, complementary metamaterials enables the design of a planar antenna tha ...
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Journal articleACS photonics · October 2014
The widespread use of plasmonic nanorulers (PNRs) in sensing platforms has been plagued by technical challenges associated with the development of methods to fabricate precisely controlled nanostructures with high yield and characterize them with high thro ...
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Journal articleIEEE Antennas and Propagation Society AP S International Symposium Digest · September 18, 2014
A low-profile, wideband transition between a coaxial waveguide and a substrate integrated waveguide (SIW) is presented in this paper. The transition is designed for a reconfigurable metamaterial antenna realized in multilayer Printed Circuit Board at X-ban ...
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Journal articlePlasma Physics and Controlled Fusion · September 1, 2014
This paper describes a detailed examination of the effects of a relatively small pulsed deuterium gas puff on the edge plasma and edge turbulence in NSTX. This gas puff caused little or no change in the line-averaged plasma density or total stored energy, ...
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Journal articleNano letters · August 2014
The radiative processes associated with fluorophores and other radiating systems can be profoundly modified by their interaction with nanoplasmonic structures. Extreme electromagnetic environments can be created in plasmonic nanostructures or nanocavities, ...
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Journal articleNuclear Fusion · August 1, 2014
This paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely (i) transition after the L- to H-mode transition, (ii) region of very steep ion t ...
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Journal articleApplied Physics Letters · July 28, 2014
We demonstrate an electrolyte-based voltage tunable vanadium dioxide (VO2) memory metasurface. Large spatial scale, low voltage, non-volatile switching of terahertz (THz) metasurface resonances is achieved through voltage application using an io ...
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Journal articleJournal of Applied Physics · July 28, 2014
We extend the discrete dipole method to enable the analysis and design of two-dimensional magnetoelectric metamaterial devices based on transformation optics. Key to this method is the evaluation of the dipole moments of the metamaterial elements, which ca ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · May 2014
We introduce a class of nonreciprocal metamaterials based on composite assemblies of metallic and biased ferrimagnetic elements. We show that such structures act as ultrathin one-way glasses due to the competition between two modes at the surface of the fe ...
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Journal articlePhysical Review D - Particles, Fields, Gravitation and Cosmology · April 9, 2014
A facility that can deliver beams of electron and muon neutrinos from the decay of a stored muon beam has the potential to unambiguously resolve the issue of the evidence for light sterile neutrinos that arises in short-baseline neutrino oscillation experi ...
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Journal articleScientific reports · February 2014
Synergistic integration of electromagnetic (EM) and mechanical properties of metamaterials, a concept known as smart metamaterials, promises new applications across the spectrum, from flexible waveguides to shape-conforming cloaks. These applications becam ...
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Journal articleApplied Physics Letters · January 13, 2014
Film-coupled nanoparticle systems have proven a reliable platform for exploring the field enhancement associated with sub-nanometer sized gaps between plasmonic nanostructures. In this Letter, we present a side-by-side comparison of the spectral properties ...
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Journal articleScientific reports · January 2014
The ability to wirelessly power electrical devices is becoming of greater urgency as a component of energy conservation and sustainability efforts. Due to health and safety concerns, most wireless power transfer (WPT) schemes utilize very low frequency, qu ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · January 1, 2014
Imaging in long wavelength regimes holds huge potential in many fields, from security to skin cancer detection. However, it is often difficult to image at these frequencies - the so called 'THz gap1' is no exception. Current techniques generally ...
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Journal articleNature Photonics · January 1, 2014
Imaging at long wavelengths, for example at terahertz and millimetre-wave frequencies, is a highly sought-after goal of researchers because of the great potential for applications ranging from security screening and skin cancer detection to all-weather nav ...
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Journal articleIEEE MTT S International Microwave Symposium Digest · January 1, 2014
This paper presents an experimental study analyzing the effects of surface treated Polyimide (PI) on dielectric anisotropy and response time of Liquid Crystal (LC) in an In-Plane Switching (IPS) cell design. A Co-Planar Waveguide (CPW) transmission line is ...
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Journal articleIEEE Antennas and Propagation Magazine · January 1, 2014
This work describes how indirect holographic techniques, previously applied to the determination of antenna radiation patterns, can be adapted for the imaging of passive objects. It provides details of how complex scattered field values can be obtained in ...
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Journal articleIEEE Transactions on Electron Devices · January 1, 2014
This paper presents a new radio frequency (RF) excited plasma cathode electron beam (EB) gun design and experimental results at a frequency of 84 MHz. The design offers the following benefits over thermionic cathode triode EB guns: much longer cathode life ...
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Journal articleOptics express · December 2013
We analyze the resonant electromagnetic response of sub-wavelength plasmonic dimers formed by two silver strips separated by a thin dielectric spacer and embedded in a uniform dielectric media. We demonstrate that the off-resonant electric and resonant, ge ...
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Journal articleInternational Conference on Infrared Millimeter and Terahertz Waves Irmmw Thz · December 1, 2013
Dispersive imagers measure multiple speckle realizations of the object to be estimated. This poses a challenge for coherent imaging as classically objects are backpropagated and then despeckled. We present initial findings on an intensity based method for ...
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Journal articleAsia Pacific Microwave Conference Proceedings APMC · December 1, 2013
We introduce a microwave cloak composed of smart metamaterials whose electromagnetic properties can be effectively changed by mechanical deformation. Against mechanical deformations, our smart metamaterials self-adjust own flexible elasto-electromagnetic c ...
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Journal articleIEEE Antennas and Propagation Society AP S International Symposium Digest · December 1, 2013
We demonstrate the use of a metamaterial to transition between a guided surface mode and a designed radiative aperture distribution. Plots of the field distribution at incremental distances removed from the aperture plane illustrate the transformation from ...
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Journal articleOptics InfoBase Conference Papers · December 1, 2013
Clever structuring of dielectric and metallic composites can lead to effective electric, magnetic and anisotropic responses. When hybridized with nonlinear components, such 'metamaterials' can support a wide range of nonlinear properties characterized by e ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · November 25, 2013
Metamaterial engineering offers a route to combine unusual and interesting optical phenomena in ways that are rare or nonexistent in nature. As an exploration of this wide parameter space, we experimentally demonstrate strong cross-phase modulation and fou ...
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Journal articleElectronics Letters · November 21, 2013
A novel combination of a two-port slant ± 45° dual-polarised microstrip patch antenna with a polycrystalline silicon (poly-Si) solar cell operating as an RF stacked parasitic patch element is presented and discussed for 5.8 GHz band polarisation diverse mu ...
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Journal articleJournal of the Optical Society of America B Optical Physics · November 1, 2013
We present a step-by-step analysis of four-wave mixing (FWM) in one-dimensional stacks of metallo-dielectric structures, pointing out various channels of plasmonic and Fabry-Perot enhancement. We start from the derivation of oblique incidence FWM at a sing ...
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Journal articlePhotonics and Nanostructures Fundamentals and Applications · November 1, 2013
We analyze the properties of complementary metamaterials as effective inclusions patterned into the conducting walls of metal waveguide structures. We show that guided wave metamaterials can be homogenized using the same retrieval techniques used for volum ...
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Journal articleNuclear Fusion · November 1, 2013
Previous pedestal turbulence measurements in the National Spherical Torus Experiment assessed the spatial and temporal properties of turbulence in the steep gradient region of H-mode pedestals during edge localized mode (ELM)-free, MHD-quiescent periods. H ...
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Journal articleOptics express · November 2013
This paper presents an optical element capable of multiplexing two diffraction patterns for two orthogonal linear polarizations, based on the use of non-resonant metamaterial cross elements. The metamaterial cross elements provide unique building blocks fo ...
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Journal articleJournal of Applied Physics · October 28, 2013
We present an analytical treatment of the optical scattering from film-coupled nanocubes. Film-coupled nanoparticles are a convenient platform for the demonstration of a variety of fundamental plasmonic phenomena, including nonlocality and field enhancemen ...
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Journal articleNuclear Fusion · October 1, 2013
Research on the National Spherical Torus Experiment, NSTX, targets physics understanding needed for extrapolation to a steady-state ST Fusion Nuclear Science Facility, pilot plant, or DEMO. The unique ST operational space is leveraged to test physics theor ...
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Journal articleJournal of the Optical Society of America B Optical Physics · October 1, 2013
We examine the optical scattering from a variety of axially symmetric plasmonic nanoparticle dimers separated by nanoscale gaps, quantifying the role of classical nonlocality on their optical properties. Due to the rotational symmetry of the analyzed struc ...
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Journal articleNuclear Fusion · September 1, 2013
Progress in characterizing the edge stability and properties of the microinstabilities responsible for enhanced transport in the pedestal region is reported. The stability of the pedestal is characterized in high performance discharges on National Spherica ...
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Journal articleOptics letters · September 2013
Planar plasmonic devices are becoming attractive for myriad applications, owing to their potential compatibility with standard microelectronics technology and the capability for densely integrating a large variety of plasmonic devices on a chip. Mitigating ...
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Journal articleNuclear Fusion · August 1, 2013
Microturbulence is considered to be a major candidate in driving anomalous transport in fusion plasmas, and the equilibrium E × B shear generated by externally driven flow can be a powerful tool to control microturbulence in future fusion devices such as F ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · August 2013
We introduce the concept of a metamaterial aperture, in which an underlying reference mode interacts with a designed metamaterial surface to produce a series of complex field patterns. The resonant frequencies of the metamaterial elements are randomly dist ...
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Journal articleApplied Physics Letters · July 15, 2013
We investigate computationally the electromagnetic response of composite media made from high-aspect ratio nanoparticle arrays. The shape and local ordering of the nanoparticles can be used to both confine and enhance the local electric fields induced in r ...
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Journal articleNature Physics · July 1, 2013
Would you ever guess that a microscopic flake of graphite could reverse the diffraction of light? An experiment that demonstrates just such an effect highlights the exciting optical applications of graphene — an atomic layer of carbon with a two-dimensiona ...
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Journal articleApplied Physics Letters · June 3, 2013
Creation and control of spatial gradients in electromagnetic properties is a central theme underlying optical device design. In this work, we demonstrate that through modification of the spatial and temporal distribution of current, we can obtain increased ...
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Journal articlePhysics of Plasmas · May 1, 2013
The spherical torus edge region is among the most challenging regimes for plasma turbulence simulations. Here, we measure the spatial and temporal properties of ion-scale turbulence in the steep gradient region of H-mode pedestals during edge localized mod ...
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Journal articleOptics letters · May 2013
We report stereolithographic polymer-based fabrication and experimental operation of a microwave X-band cloaking device. The device is a relatively thin (about one wavelength thick) shell of an air-dielectric composite, in which the dielectric component ha ...
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Journal articleIEEE Microwave and Wireless Components Letters · April 30, 2013
This letter presents a novel low-profile quad-bandsolar PIFA which has the potential to be employed in self-powered low-power GSM 1800, 2.4 GHz band WLAN and 2.3/3.3/5.8 GHz band WiMAX networks. The multi-slot loaded radiating PIFA element consisting of W- ...
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Journal articleElectronics Letters · April 25, 2013
A novel combination of a parametrically optimised UWB meshed circular disc monopole antenna with a polycrystalline silicon (poly-Si) solar cell is presented and discussed. The results indicate that the fabricated meshed solar monopole antenna operates acro ...
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Journal articleChemphyschem : a European journal of chemical physics and physical chemistry · April 2013
In this concept, we present the basic assumptions and techniques underlying the hydrodynamic model of electron response in metals and demonstrate that the model can be easily incorporated into computational models. We discuss the role of the additional bou ...
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Journal articleOptics express · April 2013
Axisymmetric radiating and scattering structures whose rotational invariance is broken by non-axisymmetric excitations present an important class of problems in electromagnetics. For such problems, a cylindrical wave decomposition formalism can be used to ...
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Journal articleIEEE Transactions on Nuclear Science · March 26, 2013
This paper provides information regarding the use of the Xilinx Virtex-4 field-programmable gate array (FPGA) in a spacecraft deployed to low-earth orbit. The results are compared to pre-deployment accelerated single-event effects (SEEs) and fault-injectio ...
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Journal articlePhysical review letters · February 2013
When both electric and magnetic mechanisms contribute to a particular nonlinear optical process, there exists the possibility for nonlinear interference, often characterized by constructive or destructive interference in the radiation pattern of harmonics ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · January 2, 2013
We analyze the impact of nonlocality on the waveguide modes of metallodielectric multilayers and optical patch antennas, the latter formed from metal strips closely spaced above a metallic plane. We model both the nonlocal effects associated with the condu ...
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Journal article2013 7th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics Metamaterials 2013 · January 1, 2013
The rapid evolution of additive manufacturing techniques has the potential to revolutionize a wide range of fabrication-limited fields. In this article, we apply plastic additive manufacturing to the creation of radio-frequency electromagnetic devices, dem ...
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Journal articleIEEE Transactions on Antennas and Propagation · January 1, 2013
A super wideband printed modified bow-tie antenna loaded with rounded-T shaped slots fed through amicrostrip balun is proposed for microwave and millimeter-wave band imaging applications. The modified slot-loaded bow-tie pattern increases the electrical le ...
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Journal articleProgress in Electromagnetics Research · January 1, 2013
A novel microwave imaging approach for early stage breast cancer detection is described. The proposed technique involves the use of an Indirect Microwave Holographic technique employing a patented synthetic reference wave. This approach offers benefits in ...
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Journal articleIEEE Transactions on Antennas and Propagation · January 1, 2013
This communication presents a simplified design approach to obtain the turns ratio Nf which models the coupling between the microstrip feed and slot line of an aperture coupled slot antenna by using the S11 parameter. Equations are de ...
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Journal articleProgress in Electromagnetics Research · January 1, 2013
In this paper, a novel self-complementary shaped multiple- L slot loaded suspended microstrip patch antenna stacked with a polycrystalline silicon (poly-Si) solar cell is presented for 2.4/5.2GHz band WLAN and 2.5/3.3/5.8 GHz band WiMAX networks. While the ...
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Journal articlePhysics of Plasmas · January 1, 2013
Characterization of the spatial structure of turbulence fluctuations during the edge localized mode cycle in the pedestal region is reported. Using the beam emission spectroscopy and the correlation reflectometry systems, measurements show spatial structur ...
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Journal articleNature materials · January 2013
Invisibility is a notion that has long captivated the popular imagination. However, in 2006, invisibility became a practical matter for the scientific community as well, with the suggestion that artificially structured metamaterials could enable a new elec ...
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Journal articleScience (New York, N.Y.) · January 2013
By leveraging metamaterials and compressive imaging, a low-profile aperture capable of microwave imaging without lenses, moving parts, or phase shifters is demonstrated. This designer aperture allows image compression to be performed on the physical hardwa ...
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Journal articleNano letters · January 2013
A metallic nanoparticle positioned over a metal film offers great advantages as a highly controllable system relevant for probing field-enhancement and other plasmonic effects. Because the size and shape of the gap between the nanoparticle and film can be ...
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Journal article2012 Conference on Lasers and Electro Optics CLEO 2012 · December 6, 2012
Metamaterials provide resources for the development of unconventional optical devices and the improvement of conventional ones. We review the methods of analyzing, constructing and characterizing metamaterials, and discuss their extension to infrared and v ...
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Journal articleOptics InfoBase Conference Papers · December 1, 2012
Metamaterials provide resources for the development of unconventional optical devices and the improvement of conventional ones. We review the methods of analyzing, constructing and characterizing metamaterials, and discuss their extension to infrared and v ...
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Journal articleNature · December 2012
Efficient and tunable absorption is essential for a variety of applications, such as designing controlled-emissivity surfaces for thermophotovoltaic devices, tailoring an infrared spectrum for controlled thermal dissipation and producing detector elements ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · November 2012
We demonstrate that fluid flow cloaking solutions, based on active hydrodynamic metamaterials, exist for two-dimensional flows past a cylinder in a wide range of Reynolds numbers (Re's), up to approximately 200. Within the framework of the classical Brinkm ...
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Journal articleOptics letters · November 2012
The possibility of making an optically large (many wavelengths in diameter) object appear invisible has been a subject of many recent studies. Exact invisibility scenarios for large (relative to the wavelength) objects involve (meta)materials with superlum ...
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Journal articleJournal of the Optical Society of America. A, Optics, image science, and vision · November 2012
We analyze the Seidel wavefront aberrations and spot sizes of gradient index (GRIN) singlet lenses with Δn≈1. We consider and compare curved and planar GRIN lenses with F-numbers of 5 and 1 against equivalent refractive lenses. We find that the planar GRIN ...
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Journal articleACS nano · October 2012
We demonstrate a plasmon nanoruler using a coupled film nanoparticle (film-NP) format that is well-suited for investigating the sensitivity extremes of plasmonic coupling. Because it is relatively straightforward to functionalize bulk surface plasmon suppo ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · September 27, 2012
We present a numerical investigation of the second-order nonlinear optical properties of metal-based metamaterial nanoresonators. The nonlinear optical response of the metal is described by a hydrodynamic model, with the effects of electron pressure in the ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · September 17, 2012
In this work, we experimentally and theoretically explore voltage-controlled oscillations occurring in microbeams of vanadium dioxide. These oscillations are a result of the reversible insulator-to-metal phase transition in vanadium dioxide. By examining t ...
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Journal articlePhysical Review A Atomic Molecular and Optical Physics · September 12, 2012
Artificially structured metamaterials hybridized with elements that respond nonlinearly to incident electromagnetic fields can, from a macroscopic perspective, support nonlinear responses that cannot be described by purely electric or magnetic interactions ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · August 8, 2012
Reconfigurable metamaterial-based apertures can play a unique role in both imaging and in beam-forming applications, where current technology relies mostly on the fabrication and integration of large detector or antenna arrays. Here, we report the experime ...
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Journal articleScience (New York, N.Y.) · August 2012
Our intuitive understanding of light has its foundation in the ray approximation and is intimately connected with our vision. As far as our eyes are concerned, light behaves like a stream of particles. We look inside the wavelength and study the properties ...
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Journal articleScience (New York, N.Y.) · August 2012
Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenome ...
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Journal articleApplied Physics Letters · July 30, 2012
We demonstrate nonlinear magnetoelectric coupling in a varactor-loaded metamaterial at microwave frequencies. The nonlinear magnetoelectric coupling takes the form of second-harmonic generation in which incident magnetic fields at frequency ω drive an elec ...
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Journal articleIEEE Antennas and Propagation Magazine · July 17, 2012
Metamaterials are typically engineered by arranging a set of small scatterers or apertures in a regular array throughout a region of space, thus obtaining some desirable bulk electromagnetic behavior. The desired property is often one that is not normally ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · July 11, 2012
The e2v technologies Swept Charge Device (SCD) was developed as a large area detector for X-ray Fluorescence (XRF) analysis, achieving near Fano-limited spectroscopy at -15 °C. The SCD was flown in the XRF instruments onboard the European Space Agency's SM ...
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Journal articleJournal of Applied Physics · June 15, 2012
Transformation optics (TO) is a powerful tool for the design of electromagnetic and optical devices with novel functionality derived from the unusual properties of the transformation media. In general, the fabrication of TO media is challenging, requiring ...
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Journal articleOptics letters · June 2012
When an electromagnetic wave is obliquely incident on the interface between two homogeneous media with different refractive indices, the requirement of phase continuity across the interface generally leads to a shift in the trajectory of the wave. When a l ...
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Journal articleOptics express · June 2012
We demonstrate both the beam-forming and imaging capabilities of an X-band (8-12 GHz) operational Lüneburg lens, one side of which has been flattened via a coordinate transformation optimized using quasi-conformal transformation optics (QCTO) procedures. O ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · May 15, 2012
We present a study of the second-order nonlinear optical properties of metal-based metamaterials. A hydrodynamic model for electronic response is used, in which nonlinear surface contributions are expressed in terms of the bulk polarization. The model is i ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · May 4, 2012
The plasmonic modes of a nano-antenna formed by a nanoparticle/thin film hybrid system are investigated. Plasmonic nano-antennas are well-known for their capabilities to concentrate electromagnetic wave into extreme small region and couple the emission fro ...
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Journal articlePhysics of Plasmas · May 1, 2012
Electron-scale turbulence is predicted to drive anomalous electron thermal transport. However, experimental study of its relation with transport is still in its early stage. On the National Spherical Tokamak Experiment (NSTX), electron-scale density fluctu ...
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Journal articlePhysics of Plasmas · May 1, 2012
The National Spherical Torus Experiment (NSTX) [M. Ono, Nucl. Fusion 40, 557 (2000)] can achieve high electron plasma confinement regimes that are super-critically unstable to the electron temperature gradient driven (ETG) instability. These plasmas, dubbe ...
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Journal articleOptics express · May 2012
We consider the process of four-wave mixing in an array of gold nanowires strongly coupled to a gold film. Using full-wave simulations, we perform a quantitative comparison of the four-wave mixing efficiency associated with a bare film and films with nanow ...
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Journal articleNano letters · April 2012
The localized surface plasmon resonance (LSPR) spectrum associated with a gold nanoparticle (NP) coupled to a gold film exhibits extreme sensitivity to the nanogap region where the fields are tightly localized. The LSPR of an ensemble of film-coupled NPs c ...
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Journal articleJournal of Applied Physics · March 15, 2012
We investigate numerically the use of a negative-permeability perfect lens for enhancing wireless power transfer between two current carrying coils. The negative permeability slab serves to focus the flux generated in the source coil to the receiver coil, ...
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Journal articleNature materials · March 2012
As a result of advances in nanotechnology and the burgeoning capabilities for fabricating materials with controlled nanoscale geometries, the traditional notion of what constitutes an optical device continues to evolve. The fusion of maturing low-cost lith ...
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Journal articleJournal of Applied Physics · March 1, 2012
We propose a generalization of the two-dimensional eikonal-limit cloak derived from a conformal transformation to three dimensions. The proposed cloak is a spherical shell composed of only isotropic media; it operates in the transmission mode and requires ...
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Journal articleJournal of Intelligent Material Systems and Structures · March 1, 2012
Analogous to mechanical systems, modeling the electromagnetic (EM) performance of large and complex metamaterial structures requires the use of effective-medium/constitutive properties. Constitutive properties are critical for efficiently bridging the gap ...
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Journal articleNew Journal of Physics · March 1, 2012
We develop a numerical technique for simulating metamaterial electromagnetic response based on an adaptation of the discrete dipole approximation (DDA). Our approach reduces each constituent metamaterial element within the composite to a point dipole with ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · February 27, 2012
We propose that macroscopic objects built from negative-permeability metamaterials may experience resonantly enhanced magnetic force in low-frequency magnetic fields. Resonant enhancement of the time-averaged force originates from magnetostatic surface res ...
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Journal articleApplied Physics Letters · February 20, 2012
Low coherence backscattering (LCBS) is a proposed diagnostic technique for measuring plasma turbulence and fluctuations. LCBS is an adaptation of optical coherence tomography, a biomedical imaging technique. Calculations and simulations show LCBS measureme ...
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Journal articleNuclear Fusion · January 1, 2012
In the National Spherical Torus Experiment (NSTX), a large increase in the charge exchange neutral flux localized around the neutral beam (NB) injection full energy is measured using a neutral particle analyser. Termed the high-energy feature (HEF), it app ...
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Journal articleOptics express · January 2012
Employing artificially structured metamaterials provides a means of circumventing the limits of conventional optical materials. Here, we use transformation optics (TO) combined with nanolithography to produce a planar Luneburg lens with a flat focal surfac ...
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Journal articleNature communications · January 2012
The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. ...
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Journal articleOptics InfoBase Conference Papers · December 1, 2011
Third-order nonlinear response and strong field enhancement in gold nanocomposites are utilized to analyze the enhanced effective nonlinear susceptibility, subwavelength field confinement and reduced bend radii in the evanescent and propagating regimes of ...
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Journal articlePhysical Review X · December 1, 2011
We computationally and experimentally investigate the use of metamaterial resonators as bandpass filters and other components that enable control of guided surface electromagnetic waves. The guided surface electromagnetic wave propagates on a planar Goubau ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · December 1, 2011
The equivalent of a blazed diffraction grating can be formed from an array of metamaterial elements arranged so as to produce a linear gradient in the effective refractive index. By spreading the gradient over a multiwavelength distance, and repeating the ...
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Journal articlePhysical Review A Atomic Molecular and Optical Physics · November 2, 2011
Artificially structured metamaterials offer a means to enhance the weak optical nonlinearities of natural materials. The enhancement results from the inhomogeneous nature of the metamaterial unit cell, over which the local field distribution can likewise b ...
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Journal articleOptics express · November 2011
We demonstrate the design, fabrication and characterization of an artificially structured, gradient index metamaterial with a linear index variation of Δn ~ 3.0. The linear gradient profile is repeated periodically to form the equivalent of a blazed gratin ...
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Journal articleOptical Materials Express · November 1, 2011
Nonlinear metamaterials have potentially interesting applications in highly efficient wave-mixing and parametric processes, owing to their ability to combine enhanced nonlinearities with exotic and configurable linear properties. However, the strong disper ...
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Journal articlePlanetary and Space Science · October 1, 2011
We have conducted laboratory experiments as an analogue to planetary XRF (X-ray fluorescence) missions in order to investigate the role of changing incidence (and phase) angle geometry and sample grain-size on the intensity of XRF from regolith-like sample ...
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Journal articleNuclear Fusion · September 1, 2011
In the last two experimental campaigns, the low aspect ratio NSTX has explored physics issues critical to both toroidal confinement physics and ITER. Experiments have made extensive use of lithium coatings for wall conditioning, correction of non-axisymmet ...
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Journal articleOptics express · September 2011
Using a finite-element, full-wave modeling approach, we present a flexible method of analyzing and simulating dielectric and plasmonic waveguide structures as well as their mode coupling. This method is applied to an integrated plasmonic circuit where a st ...
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Journal articlePlasma Physics and Controlled Fusion · August 1, 2011
Beam-emission spectroscopy (BES) diagnostics normally detect fluctuations in the light emitted by an injected neutral beam. Under some circumstances, however, light from fast ions that charge exchange in the high neutral-density region at the edge of the p ...
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Journal articlePhysical review letters · August 2011
We introduce a new concept for the manipulation of fluid flow around three-dimensional bodies. Inspired by transformation optics, the concept is based on a mathematical idea of coordinate transformations and physically implemented with anisotropic porous m ...
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Journal articlePhysical review letters · August 2011
Nonlinear metamaterials have been predicted to support new and exciting domains in the manipulation of light, including novel phase-matching schemes for wave mixing. Most notable is the so-called nonlinear-optical mirror, in which a nonlinear negative-inde ...
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Journal articleApplied Physics Letters · July 25, 2011
We demonstrate tuning of a metamaterial device that incorporates a form of spatial gradient control. Electrical tuning of the metamaterial is achieved through a vanadium dioxide layer which interacts with an array of split ring resonators. We achieved a sp ...
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Journal articlePhysical Review A Atomic Molecular and Optical Physics · July 21, 2011
The ability to tune the quasi-phase-matching (QPM) frequency is a highly desirable though lacking feature of many nonlinear devices. To this end, we consider QPM in a special class of active nonlinear metamaterials (MMs), whose properties can be controlled ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · July 13, 2011
The solutions to the Rotman lens design equations constrain the minimum size of the device. Here we use Transformation Optics to compress a transmission line based Rotman lens by 27 percent along the optical axis while maintaining the beam steering range, ...
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Journal articleMicrowave and Optical Technology Letters · July 1, 2011
Transformation optics is a methodology that has proven useful in the design of complex media used to alter and control electromagnetic waves in either passive space or regions that contain source distributions. Recently it has been shown that the applicati ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · May 18, 2011
Nonradiative coupling between conductive coils is a candidate mechanism for wireless energy transfer applications. In this paper we propose a power relay system based on a near-field metamaterial superlens and present a thorough theoretical analysis of thi ...
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Journal articleApplied Physics Letters · May 16, 2011
We present experimental measurements of three- and four-wave mixing phenomena in an artificially structured nonlinear magnetic metacrystal at microwave frequencies. The sum frequency generation signal for the varactor-loaded split-ring resonator (VLSRR) me ...
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Journal articlePhysical Review Letters · April 22, 2011
In this Letter we report the first clear experimental observation of density gradient stabilization of electron temperature gradient driven turbulence in a fusion plasma. It is observed that longer wavelength modes, kρs10, are most st ...
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Journal articleOptics express · April 2011
We verify numerically and experimentally the accuracy of an analytical model used to derive the effective nonlinear susceptibilities of a varactor-loaded split ring resonator (VLSRR) magnetic medium. For the numerical validation, a nonlinear oscillator mod ...
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Journal articleJournal of Applied Physics · April 1, 2011
In this paper, we analytically describe the strain-dependent effective medium properties for a metamaterial electric-LC (ELC) resonator, commonly used in metamaterial designs to provide a tailored electric response to electromagnetic waves. Combining an eq ...
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Journal articlePlasma Physics and Controlled Fusion · March 1, 2011
Gyrokinetic calculations indicate microtearing modes below the ion gyroscale are linearly unstable in a National Spherical Torus Experiment (NSTX) plasma. The modes are robustly unstable with respect to simulation parameters, radial location and discharge ...
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Journal articlePlasmonics · March 1, 2011
We report a morphology-correlated surface-enhanced Raman scattering (SERS) from molecules on the surface of individual clusters of gold nanoparticles of two types and compare the signal from clusters of two, three, four, and five nanoparticles with the sig ...
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Journal articlePhysical Review Letters · February 3, 2011
Negative magnetic shear is found to suppress electron turbulence and improve electron thermal transport for plasmas in the National Spherical Torus Experiment (NSTX). Sufficiently negative magnetic shear results in a transition out of a stiff profile regim ...
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Journal articleJournal of Optics · January 1, 2011
We review several approaches to optical invisibility designed using transformation optics (TO) and optical conformal mapping (CM) techniques. TO is a general framework for solving inverse scattering problems based on mimicking spatial coordinate transforma ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 2011
We apply an analytic theory [New J. Phys. 12, 093010 (2010)] toward the design of varactor-loaded split-ring resonator metacrystals, having nonlinear electromagnetic properties on demand. The design methodology here is shown to be efficient and is validate ...
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Journal articleProceedings of the IEEE · January 1, 2011
Transformation optics is an emerging technique for the design of advanced electromagnetic media. Transformation optical devices exploit the form invariance of Maxwell's equations, allowing geometry to play the dominant role in the design process rather tha ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 2011
We consider the design and implementation of a two-dimensional metamaterial relay lens, conceptually formed by flattening a Maxwell fisheye lens-a perfect imaging device-through the use of a coordinate transformation. Because Maxwell's equations are form-i ...
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Journal articleSensors (Basel, Switzerland) · January 2011
The Luneburg lens is a powerful imaging device, exhibiting aberration free focusing for parallel rays incident from any direction. However, its advantages are offset by a focal surface that is spherical and thus difficult to integrate with standard planar ...
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Journal article · December 1, 2010
Loss and bandwidth have been major problems that limit the potential applications on metamaterials for a long time. To bring the ultimate opportunity to metamaterials, we analyze and discuss, in this chapter, another type of metamaterials that perform at l ...
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Journal article · December 1, 2010
In this chapter some experiments and applications of metamaterials in the microwave regime have been presented. Although metamaterials are composed of structures with finite periodicity, they can still be regarded as effective medium when the periodicity i ...
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Journal article · December 1, 2010
In this chapter, we present a general theory of effective media to establish the relationship between the local field responses on metamaterial structure and the macroscopical behaviors for artificial metamaterials composed of periodic resonant structures. ...
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Journal articleMetamaterials Theory Design and Applications · December 1, 2010
Metamaterials: Theory, Design and Applications focuses on the most recent research activity in metamaterials, taking a reader beyond previously covered areas like left-handed materials (LHM) and negative index materials (LIM). Some new developments covered ...
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Journal article · December 1, 2010
In this chapter, we will discuss the approach of utilizing transformation optic approach and metamaterial technology to construct various cloaking devices in experiment. We take the advantage of rapid design approach to demonstrate the reduced cloaking dev ...
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Journal article · December 1, 2010
There have been increasing interests in metamaterials in the past 10 years in the scientific communities. However, metamaterials are sometimes regarded as left-handed materials or negative refractive index materials by a lot of people including researchers ...
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Journal article · December 1, 2010
Metamaterials are generally composed of sub-wavelength structures with designable geometries. The macroscopic properties of metamaterials are harnessed by engineering the geometric dimensions of the particles. During the past few years, designing metamater ...
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Journal articleMetamaterials · December 1, 2010
We spectroscopically investigate the scaling properties of a metamaterial consisting of a square array of gold cylindrical dots. The electromagnetic response of the gold-dot array is found to scale in relation to the ratio of the incident wavelength over t ...
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Journal articleAdvances in Civil Engineering · December 1, 2010
The low-cost, widespread availability and robust nature of current electronic devices suggest the feasibility of creating a composite structure with integrated networked sensors to monitor in real time the life of civil and aerospace structures while in se ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · November 17, 2010
We present an artificial dielectric material designed to operate at W-band millimeter-wave frequencies. The artificial dielectric exhibits a wide range of variation in its effective refractive index, making it suitable for use in planar gradient index (GRI ...
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Journal articleApplied Physics Letters · November 8, 2010
In this paper, we describe the strain-dependent behavior of an electric-LC (ELC) resonator unit cell, commonly used in metamaterial designs. We leverage analytic expression to understand the way strain manifests itself in a change in electromagnetic (EM) r ...
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Journal articlePhysics of Plasmas · November 1, 2010
Comparison between spectra of short-scale density fluctuations measured with coherent electromagnetic scattering experiments and those extracted from space-resolved numerical simulations is affected by a number of systematic errors. These include the local ...
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Journal articlePhysical review letters · November 2010
We introduce an approach to the design of three-dimensional transformation optical (TO) media based on a generalized quasiconformal mapping approach. The generalized quasiconformal TO (QCTO) approach enables the design of media that can, in principle, be b ...
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Journal articleACS nano · November 2010
Surface plasmons supported by metal nanoparticles are perturbed by coupling to a surface that is polarizable. Coupling results in enhancement of near fields and may increase the scattering efficiency of radiative modes. In this study, we investigate the Ra ...
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Journal articleNano letters · October 2010
The strongly enhanced and localized optical fields that occur within the gaps between metallic nanostructures can be leveraged for a wide range of functionality in nanophotonic and optical metamaterial applications. Here, we introduce a means of precise co ...
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Journal articlePhysical review letters · October 2010
We introduce a class of optical media based on adiabatically modulated, dielectric-only, and potentially extremely low-loss, photonic crystals (PC). The media we describe represent a generalization of the eikonal limit of transformation optics (TO). The ba ...
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Journal articlePhysical Review A Atomic Molecular and Optical Physics · September 13, 2010
We report on plasmonic waveguides made of a thin metal stripe surrounded on one or both sides by a Kerr nonlinear medium. Using an iterative numerical method, we investigate the stationary long-range plasmons that exist for self-focusing and self-defocusin ...
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Journal articleNew Journal of Physics · September 6, 2010
We analyze the properties of a nonlinear metamaterial formed by integrating nonlinear components or materials into the capacitive regions of metamaterial elements. A straightforward homogenization procedure leads to general expressions for the nonlinear su ...
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Journal articleOptics express · September 2010
We apply the transformation optical technique to modify or improve conventional refractive and gradient index optical imaging devices. In particular, when it is known that a detector will terminate the paths of rays over some surface, more freedom is avail ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · September 2010
We present a generalized nonlinear susceptibility retrieval method for metamaterials based on transfer matrices and valid in the nondepleted pump approximation. We construct a general formalism to describe the transfer matrix method for nonlinear media and ...
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Journal articleIet Microwaves Antennas and Propagation · August 1, 2010
This work investigates the gains realisable through the use of artificially structured materials, otherwise known as metamaterials, in the wide angle impedance matching (WAIM) of waveguide-fed phased-array antennas. The authors propose that the anisotropic ...
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Journal articleNew Journal of Physics · July 12, 2010
We propose a general methodology and a set of practical recipes for the construction of ultra-broadband acoustic cloaks-structures that can render themselves and a concealed object undetectable by means of acoustic scattering. The acoustic cloaks presented ...
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Journal articleApplied Physics Letters · July 12, 2010
For many applications in gradient index devices and photonic crystals, it is necessary to be able to design semicrystalline distributions of particles where the lattice constant of the distribution is an arbitrary function of position. We propose a method ...
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Journal articleApplied Physics Letters · July 5, 2010
This letter presents a quantitative measurement of the second harmonic generated by a slab of varactor loaded split ring resonator metamaterial and the retrieval of the effective quadratic nonlinear magnetic susceptibility χ(2)musing ...
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Journal articleJournal of Composite Materials · June 1, 2010
Carbon fiber reinforced polymer (CFRP) laminates with remendable cross-linked polymeric matrices were fabricated using a modified resin transfer mold (RTM) technique. The healable composite resin, bis-maleimide tetrafuran (2MEP4F), was synthesized by mixin ...
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Journal articleIEEE Photonics Technology Letters · May 28, 2010
An InxGa1-x As thin-film inverted metalsemiconductormetal photodetector has been integrated with a gold hybrid long-range surface plasmon waveguide on silicon. This integrated structure enables planar integrated optical detection of a ...
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Journal articleNew Journal of Physics · April 22, 2010
We present experimental quantitative scattering cross-section (SCS) measurements for a metamaterial cloak. The cloak is nearly identical to that reported in 2006; however, quantitative experimental measurements have not yet been reported for such a structu ...
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Journal articleOptics Communications · April 15, 2010
We perform numerical simulations demonstrating parametric generation and oscillation processes in a single-layer of metamaterial composed of split ring resonators (SRRs). In general, a parametric resonance is achieved by introducing a time-modulation of on ...
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Journal articleOptics Communications · April 15, 2010
Metamaterials are engineered periodic structures for which it is possible to assign effective homogenized constitutive properties. In recent years, metamaterials in which the constituent elements are integrated with inherently nonlinear materials or electr ...
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Journal articleApplied Physics Letters · March 26, 2010
We present an analysis of the nonlinear, power-dependent resonance frequency shift for two metamaterial mediums consisting of arrays of varactor-loaded split ring resonators (VLSRRs). We confirm that, over a limited range of power, a VLSRR medium can be de ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · March 2010
Electromagnetic metamaterials are artificially structured media typically composed of arrays of resonant electromagnetic circuits, the dimension and spacing of which are considerably smaller than the free-space wavelengths of operation. The constitutive pa ...
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Journal articleNature materials · February 2010
For centuries, the conventional approach to lens design has been to grind the surfaces of a uniform material in such a manner as to sculpt the paths that rays of light follow as they transit through the interfaces. Refractive lenses formed by this procedur ...
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Journal articleAstronomy and Astrophysics · January 1, 2010
The Spectral and Photometric Imaging REceiver (SPIRE), is the Herschel Space Observatory's submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 μm, and an imaging Fourier-transform spectrometer (F ...
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Journal articlePhysics of Plasmas · December 16, 2009
A collective scattering system has measured electron gyroscale fluctuations in National Spherical Torus Experiment [M. Ono, Nucl. Fusion 40, 557 (2000)] H-mode plasmas to investigate electron temperature gradient (ETG) turbulence. Observations and results ...
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Journal articleICCM International Conferences on Composite Materials · December 1, 2009
The field of metamaterials has seen tremendous advancements in the design, modeling, and development of structures with novel ElectroMagnetic (EM) properties. However, nothing had been done to characterize how those EM properties change when a metamaterial ...
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Journal articleICCM International Conferences on Composite Materials · December 1, 2009
A custom resin transfer molding (RTM) method for the fabrication of carbon fiber composites using thermally reversible highly cross linked polymeric matrices was developed. The resulting material quality and healing efficiency was assessed using X-ray phas ...
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Journal articleIEEE Antennas and Wireless Propagation Letters · December 1, 2009
The use of a three-dimensional electric-LC (3D-ELC) resonator to obtain a minimally refractive and strongly transmissive composite metamaterial is explored. The 3D-ELC repeated unit cell consists of two ELC elements that, when put together, may be used to ...
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Journal article2009 Conference on Lasers and Electro Optics and 2009 Conference on Quantum Electronics and Laser Science Conference CLEO QELS 2009 · November 16, 2009
We present a systematic numerical study of metamaterials integrated with gain media to achieve composite metamaterials at terahertz and infrared wavelength with reduced losses. The impact of spatial dispersion on the effective permeability resonance restor ...
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Journal articleOptics express · November 2009
Utilizing non-resonant metamaterial elements, we demonstrate that complex gradient index optics can be constructed exhibiting low material losses and large frequency bandwidth. Although the range of structures is limited to those having only electric respo ...
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Journal articleEuropean Conference on Antennas and Propagation Eucap 2009 Proceedings · October 16, 2009
We present an artificial dielectric gradient index lens designed to operate at millimeter-wave frequencies. Finite element simulations are used in conjunction with material parameter retrieval techniques to design an artificial dielectric unit cell with an ...
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Journal articlePhysics Education · September 23, 2009
A number of years have passed since the development of the 'Voyager: Satellites' educational card game reported in Physics Education in 2003. Since then, a large number of copies of the game have been produced and distributed across the UK, to a warm recep ...
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Journal articleNuclear Fusion · September 21, 2009
The first experimental assessment of low-Z impurity transport in a neutral beam heated, high-confinement H-mode plasma sustained in a low-field, low-aspect ratio spherical tokamak, was performed at the National Spherical Torus Experiment (NSTX). The inject ...
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Journal articleOptics express · September 2009
Transformation optics is widely associated with the design of unconventional electromagnetic devices, such as electromagnetic cloaks or concentrators. However, a wide range of conventional optical devices with potentially advantageous properties can be des ...
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Journal articleOptics express · September 2009
Plasmonic multi-mode interference (MMI) couplers have been investigated both numerically and experimentally at the telecommunication wavelength of 1.55 mum. In this study, the couplers are implemented using thin Au stripes that support long-range surface p ...
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Journal articleScience (New York, N.Y.) · September 2009
The resonant elements that grant metamaterials their distinct properties have the fundamental limitation of restricting their useable frequency bandwidth. The development of frequency-agile metamaterials has helped to alleviate these bandwidth restrictions ...
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Journal articleNuclear Fusion · July 2, 2009
Various theories and numerical simulations support the conjecture that the ubiquitous problem of anomalous electron transport in tokamaks may arise from a short-scale turbulence driven by the electron temperature gradient. To check whether this turbulence ...
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Journal articleApplied Physics Letters · June 18, 2009
Transformation optics can be used to design media with unique properties that alter the behavior of electromagnetic waves in passive space and recently in space containing source distributions. We present source transformations where current from a linear ...
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Journal articlePhysical Review Letters · June 5, 2009
Electron gyroscale fluctuation measurements in National Spherical Torus Experiment H-mode plasmas with large toroidal rotation reveal fluctuations consistent with electron temperature gradient (ETG) turbulence. Large toroidal rotation in National Spherical ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · June 1, 2009
The technology behind the Electron-Multiplying Charge Coupled Device (EMCCD) was successfully exploited by e2v technologies in the late 1990s. Since then, many uses have been found for these low light level (L3) devices including surveillance and many scie ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · June 1, 2009
The CCD247 is the second generation of high-resistivity device to be manufactured in e2v technologies plc development programme. Intended for infrared astronomy, the latest devices are fabricated on high resistivity (∼8 kΩ cm) bulk silicon, allowing for a ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · June 1, 2009
The e2v technologies CCD54, or swept-charge device (SCD) has been extensively radiation tested for use in the Chandrayaan-1 X-ray Spectrometer (C1XS) instrument, to be launched as a part of the Indian Space Research Organisation (ISRO) Chandrayaan-1 payloa ...
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Journal articlePlanetary and Space Science · June 1, 2009
The UK-built Chandrayaan-1 X-ray Spectrometer (C1XS) is flying as an ESA instrument on India's Chandrayaan-1 mission to the Moon. The Chandrayaan-1 mission launched on the 22nd October 2008 and entered a 100 km polar lunar orbit on the 12th November 2008. ...
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Journal articlePlanetary and Space Science · June 1, 2009
The Chandrayaan-1 X-ray Spectrometer (C1XS) is a compact X-ray spectrometer for the Indian Space Research Organisation (ISRO) Chandrayaan-1 lunar mission. It exploits heritage from the D-CIXS instrument on ESA's SMART-1 mission. As a result of detailed dev ...
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Journal articleOptics express · April 2009
Metamaterials with anisotropic electromagnetic properties have the capability to manipulate the polarization states of electromagnetic waves. We describe a method to design a broadband, low-loss wave retarder with graded constitutive parameter distribution ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · March 3, 2009
We present the theory, design, and realization of a polarization- insensitive metamaterial absorber for terahertz frequencies. Effective-medium theory is used to describe the absorptive properties of the metamaterial in terms of optical constants-a descrip ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · March 1, 2009
Two electron-multiplication, charge-coupled devices (e2v CCD97) were operated continuously for 52 days to assess their avalanche gain stability. This work was part of an evaluation study into their suitability for the radial velocity spectrometer (RVS) ins ...
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Journal articleApplied Physics Letters · February 27, 2009
Metamaterials are artificially structured materials that provide considerable flexibility for control of electromagnetic waves. The metamaterial concept can also be applied to the design of planar waveguiding structures. Here, we illustrate this design app ...
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Journal articleApplied Physics Letters · February 23, 2009
A lateral beam shift is demonstrated both theoretically and in microwave experiments when total internal reflection takes place at the boundary of a self-collimating two-dimensional photonic crystal consisting of an array of high index dielectric cylinders ...
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Journal articleCurrent Science · February 1, 2009
The Chandrayaan-1 X-ray Spectrometer (C1XS) is a compact X-ray spectrometer for the Chandrayaan-1 lunar mission. It exploits heritage from the D-C1XS instrument on ESA's SMART-1 mission. C1XS is designed to measure absolute and relative abundances of major ...
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Journal articleOptics express · February 2009
We consider the hybridization of the resonance of a SRR metamaterial with the gyromagnetic material resonance of yittrium iron garnet (YIG) inclusions. The combination of an artificial structural resonance and natural material resonance generates a unique ...
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Journal articleNew Journal of Physics · January 16, 2009
We have designed, fabricated and characterized integrated directional couplers capable of converting the mode of an optical dielectric waveguide into a long-range plasmon propagating along a thin metal stripe. We demonstrate that the coupling between the t ...
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Journal articleOptics InfoBase Conference Papers · January 1, 2009
We present a systematic numerical study of metamaterials integrated with gain media to achieve composite metamaterials at terahertz and infrared wavelength with reduced losses. The impact of spatial dispersion on the effective permeability resonance restor ...
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Journal articleScience (New York, N.Y.) · January 2009
The possibility of cloaking an object from detection by electromagnetic waves has recently become a topic of considerable interest. The design of a cloak uses transformation optics, in which a conformal coordinate transformation is applied to Maxwell's equ ...
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Journal articleApplied Physics Letters · December 8, 2008
We present angle-resolved free-space transmission and reflection measurements of a surface composed of complementary electric inductive-capacitive (CELC) resonators. By measuring the reflection and transmission coefficients of a CELC surface with different ...
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Journal articleReview of Scientific Instruments · December 1, 2008
A collective scattering system has been installed on the National Spherical Torus Experiment (NSTX) to measure electron gyroscale fluctuations in NSTX plasmas. The system measures fluctuations with k⊥ ρ e 0.6 and k⊥ 20 cm-1. Up to five distinct ...
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Journal articleOptics express · December 2008
Transformation optics is a recently appreciated methodology for the design of complex media that control the propagation of electromagnetic and other types of waves. The transformation optical technique involves the use of coordinate transformations applie ...
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Journal articleApplied Physics Letters · December 1, 2008
Transformation optics is a recently appreciated approach for designing complex electromagnetic media. Here, we describe the extension of transformation optical techniques to include waveguide boundary conditions. We illustrate the use of finite embedded co ...
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Journal articleMeta08 Proceedings of the 2008 International Workshop on Metamaterials · December 1, 2008
Metamaterials have been rapidly explored for a few years and attracted tremendous attentions. This paper discussed the latest progress in metamaterials at microwave frequencies. The ability of designing and building the complex medium has been dramatically ...
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Journal articleMeta08 Proceedings of the 2008 International Workshop on Metamaterials · December 1, 2008
We report a broadband reflectionless gradient random medium design and experimental implementation by using metamaterial technology. This gradient random medium matches the impedance of the air and gradually change its refraction index randomly, creating a ...
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Journal articleApplied Physics Letters · November 21, 2008
An elliptical invisible cloak is proposed using a coordinate transformation in the elliptical-cylindrical coordinate system, which crushes the cloaked object to a line segment instead of a point. The elliptical cloak is reduced to a nearly circular cloak i ...
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Journal articleIEEE Transactions on Antennas and Propagation · October 27, 2008
A modification of the synthetic-plane-wave-based holographic technique for determining radiation patterns and aperture fields of medium-gain horn antennas is proposed. The modification is based on using both the sum and difference of the near field and ref ...
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Journal articleApplied Physics Letters · September 15, 2008
We demonstrate fast electrical modulation of freely propagating terahertz waves at room temperature using hybrid metamaterial devices. The devices are planar metamaterials fabricated on doped semiconductor epitaxial layers, which form hybrid metamaterial-S ...
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Journal articleConference on Quantum Electronics and Laser Science QELS Technical Digest Series · September 15, 2008
THz radiation transmission through a dual-band electric metamaterial is presented, where we analyze manufacturing defects in the metamaterial. Removing different resonator percentages allows us to quantify the effects of manufacturing defects on the materi ...
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Journal article2008 Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro Optics CLEO QELS · September 15, 2008
THz radiation transmission through a dual-band electric metamaterial is presented, where we analyze manufacturing defects in the metamaterial. Removing different resonator percentages allows us to quantify the effects of manufacturing defects on the materi ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · September 10, 2008
We have experimentally realized a two-dimensional partial focusing within a planar waveguide using complementary indefinite metamaterials. When the electric fields emitted from the dipole are TE polarized, the focusing condition requires negative magnetic ...
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Journal articleConference Proceedings 2008 IEEE International Workshop on Antenna Technology Small Antennas and Novel Metamaterials Iwat 2008 · September 1, 2008Full textCite
Journal articleNano letters · August 2008
We present an experimental analysis of the plasmonic scattering properties of gold nanoparticles controllably placed nanometers away from a gold metal film. We show that the spectral response of this system results from the interplay between the localized ...
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Journal articleOptics express · July 2008
We describe the design of adaptive beam bends and beam splitters with arbitrary bend and split angles by use of finite embedded coordinate transformations. The devices do not exhibit reflection at the entrance or exit surfaces. It is shown that moderate an ...
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Journal articleApplied Physics Letters · July 2008
We demonstrate a metamaterial device whose far-infrared resonance frequency can be dynamically tuned. Dynamic tuning should alleviate many bandwidth-related roadblocks to metamaterial application by granting a wide matrix of selectable electromagnetic prop ...
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Journal articleNano Letters · July 2008
Molecular control of plasmon coupling is investigated in sub-100 nm assemblies composed of 13 nm gold "satellite" particles tethered by reconfigurable DNA nanostructures to a 50 nm gold "core" particle. Reconfiguration of the DNA nanostructures from a comp ...
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Journal articleOptics express · June 2008
We present the design, fabrication, and measurement of a dual-band planar metamaterial with two distinct electric resonances at 1.0 and 1.2 THz, as a step towards the development of frequency agile or broadband THz materials and devices. A method of defini ...
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Journal articleApplied Physics Letters · June 2008
We study the design of arbitrarily shaped electromagnetic (EM) concentrators and their potential applications. To obtain closed-form formulas of EM parameters for an arbitrarily shaped concentrator, we employ nonuniform rational B-spline (NURBS) to represe ...
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Journal articlePhysical review letters · May 2008
We present the design for an absorbing metamaterial (MM) with near unity absorbance A(omega). Our structure consists of two MM resonators that couple separately to electric and magnetic fields so as to absorb all incident radiation within a single unit cel ...
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Journal articlePhotonics and Nanostructures Fundamentals and Applications · April 1, 2008
The technique of applying form-invariant, spatial coordinate transformations of Maxwell's equations can facilitate the design of structures with unique electromagnetic or optical functionality. Here, we illustrate the transformation-optical approach in the ...
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Journal articlePhysical Review A Atomic Molecular and Optical Physics · February 25, 2008
We report on the characterization of long-range surface plasmon waveguide bends at telecom wavelengths (λ=1550 nm). The structures consist of a thin Au stripe embedded in a transparent polymer film. When the polymer thickness is larger than the lateral ex ...
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Journal articlePhysical review letters · February 2008
Transformation optics offers an unconventional approach to the control of electromagnetic fields. The transformation optical structures proposed to date, such as electromagnetic "invisibility" cloaks and concentrators, are inherently reflectionless and lea ...
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Journal articleOptics Infobase Conference Papers · January 1, 2008
THz radiation transmission through a dual-band electric metamaterial is presented, where we analyze manufacturing defects in the metamaterial. Removing different resonator percentages allows us to quantify the effects of manufacturing defects on the materi ...
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Journal articleOptics Infobase Conference Papers · January 1, 2008
THz radiation transmission through a dual-band electric metamaterial is presented, where we analyze manufacturing defects in the metamaterial. Removing different resonator percentages allows us to quantify the effects of manufacturing defects on the materi ...
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Journal articlePhysical Review Letters · January 2008
Silveirinha and Engheta have recently proposed that electromagnetic waves can tunnel through a material with an electric permittivity (epsilon) near zero (ENZ). An ENZ material of arbitrary geometry can thus serve as a perfect coupler between incoming and ...
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Journal articlePhysical Review Letters · January 2008
Through acoustic scattering theory we derive the mass density and bulk modulus of a spherical shell that can eliminate scattering from an arbitrary object in the interior of the shell-in other words, a 3D acoustic cloaking shell. Calculations confirm that ...
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Journal articlePhysical review letters · January 2008
Silveirinha and Engheta have recently proposed that electromagnetic waves can tunnel through a material with an electric permittivity (epsilon) near zero (ENZ). An ENZ material of arbitrary geometry can thus serve as a perfect coupler between incoming and ...
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Journal articlePhysical review letters · January 2008
Through acoustic scattering theory we derive the mass density and bulk modulus of a spherical shell that can eliminate scattering from an arbitrary object in the interior of the shell--in other words, a 3D acoustic cloaking shell. Calculations confirm that ...
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Journal articleOptics and Photonics News · January 1, 2008
Long-range surface plasmons can be implemented, to develop integrated optical circuits and other chip-scale photonic applications. Long-range surface plasmons are optical modes propagating along metallic circuits at optical and near-infrared wavelengths th ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · December 21, 2007
This paper presents work carried out in support of swept-charge device (SCD) characterisation for the Chandrayaan-1 X-ray Spectrometer (C1XS) instrument. A brief overview of the C1XS instrument is presented, followed by a description of SCD structure and o ...
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Journal articleApplied Physics Letters · December 14, 2007
We demonstrate the tunneling effect in zero permittivity medium using the multilayered printed circuit, where complementary split ring resonators have been used to produce the resonant electric response and achieve the effective zero permittivity near the ...
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Journal articleConference Proceedings of the International Symposium on Signals Systems and Electronics · December 1, 2007
We have developed metamaterial unit cells whose properties can be controlled dynamically using near-infrared light. The structures consist of split ring resonators (SRRs) operating at microwave frequencies that contain a piece of low-doped silicon in their ...
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Journal articleProceedings of IEEE Sensors · December 1, 2007
The past ten years have seen a tremendous acceleration in the exploration of metals for photonic applications. This exploration has been common to both the metamaterials and the plasmonics fields, which leverage the strong resonances of structured metals t ...
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Journal articleApplied Physics Letters · November 19, 2007
Isotropic frequency selective surface (FSS) made of cubic arrangements of split ring resonators (SRRs) is proposed and analyzed. For this purpose, a suitable isotropic modification of the SRR was used in the design of a cubic unit element invariant under t ...
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Journal articleApplied Physics Letters · October 31, 2007
We investigate the effects of disorder on metamaterial samples composed of split ring resonators with randomly introduced variation in their geometrical dimensions. We demonstrate that disorder broadens the negative permeability band and introduces effecti ...
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Journal articleOptics express · October 2007
We describe transformation design of optical elements which, in addition to image transfer, perform useful operations. For one class of operations, including translation, rotation, mirroring and inversion, an image can be generated that is ideal in the sen ...
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Journal articleSpringer Series in Optical Sciences · September 26, 2007
Structures that guide waves can be found in almost every optoelectronic or photonic device. Yet, the basic principles of guided waves in practical realizations have not evolved substantially over the past several decades. At microwave or radio frequencies ...
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Journal articlePhysical Review E · September 2007
In an earlier work [Cheng and Cui, Phys. Rev. B 72, 113112 (2005)], we have shown theoretically that extremely high power densities can be generated and transmitted in a super waveguide which is filled with homogeneous bilayers of right- and left-handed ma ...
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Journal articleApplied Physics Letters · August 17, 2007
A process is demonstrated for tuning the magnetic resonance frequency of a fixed split-ring resonator array, by way of adding material near the split-ring elements. Applying drops of a silicon-nanospheres/ethanol solution to the surface of the sample decre ...
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Journal articleApplied Physics Letters · August 2, 2007
Negative index-of-refraction materials (NIMs) require both the electric permittivity and the magnetic permeability of the material to be negative. Most reported NIMs have combined conducting split ring resonators (SRRs) to realize the magnetic response and ...
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Journal articleOptics letters · August 2007
We perform rigorous simulations of hybrid long-range modes guided by a central metal core and a two-dimensional dielectric slab. We show that these modes are subject to fewer limitations than conventional long-range plasmon modes in terms of field confinem ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · August 2007
We present a general theory of effective media to set up the relationship between the particle responses and the macroscopic system behaviors for artificial metamaterials composed of periodic resonant structures. By treating the unit cell of the periodic s ...
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Journal articleApplied Physics A Materials Science and Processing · May 1, 2007
We study the coupling interaction between dielectric waveguides and coupling elements made from negative-refracting media. The coupling configuration consists of a length of dielectric waveguide, which terminates either directly into or near a planar layer ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · March 13, 2007
Artificially structured metamaterials with unit-cell dimensions on the order of 1 10th of a wavelength (λ 10) have been shown to be well approximated by an effective medium description which mimics a continuous material. In this paper we present data for t ...
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Journal articleApplied Physics Letters · March 9, 2007
The authors realize resonant crystal band gap metamaterials (CBMs) using circuit structures in the microwave regime, which behave quite differently from the conventional photonic band gap structures. They show that a periodic array of series inductor and s ...
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Journal articleIEEE Antennas and Propagation Magazine · February 1, 2007
Indirect holographic techniques offer the potential of using simple and inexpensive near-field intensity-pattern measurements for the determination of the radiation characteristics of microwave antennas, and for the reconstruction of complex aperture field ...
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Journal articleOptics express · February 2007
We perform a series of simulations and experiments at microwave frequencies where we dynamically alter the magnetic resonance of one individual split ring resonator by photodoping a piece of low-doped semiconductor positioned within the gap of the resonato ...
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Journal articleIet Microwaves Antennas and Propagation · February 1, 2007
Negative index of refraction materials (NIMs) were first postulated by Veselago in 1968 and have recently been realised using structures formed with rings and wires deposited on printed circuit boards. The proof of the existence of negative index of refrac ...
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Journal articleApplied Physics Letters · 2007
The authors present a spectroscopic analysis of a planar split-ring-resonator (SRR) medium at terahertz frequencies, quantitatively characterizing the associated magnetic resonance. Experimental quantification at terahertz and infrared frequencies of metam ...
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Journal articleIEEE Antennas and Propagation Society, AP-S International Symposium (Digest) · 2007
Microwave propagation through an eleetrie-field-coupled metamaterial lens with a refractive index gradient is experimentally investigated. A gradient in the refractive index of the metamaterial is introduced by continuous tuning of a single parameter in th ...
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Journal article6th Annual SPE Automotive Composites Conference 2006 · December 1, 2006
A novel fiber technology is being developed for the fiber reinforced composites industry. The fiber is a form of poly vinyl alcohol (PVOH). When added to conventional fiber reinforced composite PVOH fiber gives exceptional impact resistance, surface finish ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · November 21, 2006
Metamaterial structures designed to have simultaneously negative permittivity and permeability are known as left-handed materials. Their complexity and our understanding of their properties have advanced rapidly to the point where direct applications are n ...
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Journal articleIEEE Transactions on Electron Devices · November 1, 2006
This paper describes the development, operation, and characterization of charge-coupled devices (CCDs) that feature an electrode structure that allows the transfer of charge both horizontally and vertically through the image area. Such devices have been te ...
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Journal articleScience (New York, N.Y.) · November 2006
A recently published theory has suggested that a cloak of invisibility is in principle possible, at least over a narrow frequency band. We describe here the first practical realization of such a cloak; in our demonstration, a copper cylinder was "hidden" i ...
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Journal articleMicrowave and Optical Technology Letters · October 1, 2006
Original results are presented for the imaging of dielectric objects using an indirect planar microwave imaging system that employs an off-axis holographic concept. The ability of this intensity only planar recording technique to recover phase information ...
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Journal articleOptics express · October 2006
Complex and interesting electromagnetic behavior can be found in spaces with non-flat topology. When considering the properties of an electromagnetic medium under an arbitrary coordinate transformation an alternative interpretation presents itself. The tra ...
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Journal articleOptics express · September 2006
We perform an experimental study of the phase and amplitude of microwaves interacting with and scattered by two-dimensional negative index metamaterials. The measurements are performed in a parallel plate waveguide apparatus at X-band frequencies (8-12 GHz ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · September 2006
Pendry et al. have reported electromagnetically anisotropic and inhomogeneous shells that, in theory, completely shield an interior structure of arbitrary size from electromagnetic fields without perturbing the external fields. Neither the coordinate trans ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · September 2006
We explore the electromagnetic characterization of a planar artificial magnetic metamaterial. Because the composite structure is two- rather than three-dimensional, it does not form a medium with assignable bulk properties, such as the electric permittivit ...
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Journal articleJournal of Applied Physics · August 11, 2006
A medium that exhibits artificial magnetism can be formed by assembling an array of split ring resonators (SRRs) - planar conducting elements that exhibit a resonant response to electromagnetic radiation. The SRR exhibits a large magnetic dipole moment whe ...
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Journal articleMaterials Today · July 1, 2006
Engineered materials composed of designed inclusions can exhibit exotic and unique electromagnetic properties not inherent in the individual constituent components. These artificially structured composites, known as metamaterials, have the potential to fil ...
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Journal articleScience (New York, N.Y.) · June 2006
Using the freedom of design that metamaterials provide, we show how electromagnetic fields can be redirected at will and propose a design strategy. The conserved fields-electric displacement field D, magnetic induction field B, and Poynting vector B-are al ...
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Journal articleApplied Physics Letters · March 3, 2006
Metamaterial structures designed to have simultaneously negative permittivity and permeability are known as left-handed materials. Their complexity and our understanding of their properties have advanced rapidly to the point where direct applications are n ...
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Journal articleMicrowave and Optical Technology Letters · March 1, 2006
A novel indirect holographic technique for the early detection of breast cancer, which offers considerable benefits in terms of simplicity and expense, is presented and discussed. It is shown how this approach, usually employed at optical frequencies, can ...
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Journal articleApplied Physics Letters · February 6, 2006
A lithographically patterned inductive-capacitive resonator is described that has a strong electric response. This resonator can be used to construct metamaterials with desired positive or negative permittivity. Such materials provide an alternative to wir ...
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Journal articleIEEE Transactions on Electron Devices · February 1, 2006
This paper describes the irradiation of 95 electron multiplication charge coupled devices (EMCCDs) at the Paul Scherrer Institut (PSI) in Switzerland, to investigate the effects of proton irradiation on the operational characteristics of CCDs featuring ele ...
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Journal articleOptics express · February 2006
We present simulations of plasmonic transmission lines consisting of planar metal strips embedded in isotropic dielectric media, with a particular emphasis on the long-range surface plasmon polariton (SPP) modes that can be supported in such structures. Ou ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 2006
Over the past several years, metamaterials have been introduced and rapidly been adopted as a means of achieving unique electromagnetic material response. In metamaterials, artificially structured - often periodically positioned - inclusions replace the at ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 2006
We review both the theoretical electromagnetic response and the spectroscopic measurements of metamaterials. To critically examine published results for metamaterial structures operating in the range from terahertz to optical frequencies, we focus on proto ...
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Journal articleMaterials Research Society Symposium Proceedings · January 1, 2006
In the quest for ever smaller, lighter weight, and conformal components and devices for radar and communication applications, researchers in the RF community have increasingly turned to artificially engineered, composite structures (or "metamaterials") in ...
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Journal articleMicrowave and Optical Technology Letters · December 20, 2005
A novel, inexpensive technique for the detection of concealed metal objects is presented and discussed. It is shown that an indirect holographic method, usually employed at optical frequencies, can he adapted to image objects at microwave frequencies. The ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · December 13, 2005
We study the surface plasmons (SPs) that exist at the interface between air and a metamaterial constructed of split ring resonators (SRRs). The SRR metamaterial possesses a frequency band in the microwave regime (12.5-14 GHz) over which the permeability is ...
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Journal articleJoint 30th International Conference on Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics 2005 Irmmw Thz 2005 · December 1, 2005Cite
Journal articleApplied Physics Letters · August 29, 2005
A gradient index (GRIN) lens using a negative index of refraction material (NIM) has been designed and tested. The GRIN lens was fabricated using a NIM slab with a variable index of refraction perpendicular to the propagation direction. Ray tracing calcula ...
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Journal articleNew Journal of Physics · August 8, 2005
We derive a general expression for the material properties of a compensating bilayer, which is a pair of material layers which transfer the field distribution from one side of the bilayer to the other with resolution limited only by the deviation of the ma ...
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Journal articleProgress in Biomedical Optics and Imaging Proceedings of SPIE · July 21, 2005
We present S and P polarized measurements of artificial bianisotropic magnetic metamaterials with resonant behavior at infrared frequencies. These metamaterials consist of an array of micron sized (∼40μm) copper rings fabricated upon a quartz substrate. Si ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · July 11, 2005
This paper describes the proton irradiation and subsequent analysis of 8 e2v technologies CCD65 L3Vision devices with the intention of assessing the suitability of L3Vision technology to applications in space. In particular the use of L3Vision charge coupl ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · June 15, 2005
We study the frequency dependence of the effective electromagnetic parameters of left-handed and related metamaterials of the split ring resonator and wire type. We show that the reduced translational symmetry (periodic structure) inherent to these metamat ...
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Journal articlePhysics Letters Section A General Atomic and Solid State Physics · March 28, 2005
The diffraction of electromagnetic plane waves by a rectangular grating formed by discrete steps in the interface of a homogeneous, isotropic, linear, negative phase-velocity (negative index) material with free space is studied using the semi-analytic C me ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · March 2005
We discuss the validity of standard retrieval methods that assign bulk electromagnetic properties, such as the electric permittivity epsilon and the magnetic permeability mu, from calculations of the scattering (S) parameters for finite-thickness samples. ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · March 2005
Metamaterials--artificially structured materials with tailored electromagnetic response--can be designed to have properties difficult or impossible to achieve with traditional materials fabrication methods. Here we present a structured metamaterial, based ...
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Journal articleNuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms · February 1, 2005Full textCite
Journal articlePlanetary and Space Science · January 1, 2005
The increasing number of probes carrying large focal planes consisting of many charge-coupled devices (CCDs), planned to be sent to the L2 Lagrangian point, 1.5 million kilometres from Earth in the next 15 years, implies that a detailed study of the effect ...
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Journal articlePhysics World · January 1, 2005
A lens developed by physicists that can image nano-scale objects using visible light is discussed. It is found that diffraction restricts the resolution of microscopes and other optical devices to the wavelength of light used. The new superlens can produce ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · December 17, 2004
Increasingly, the demand to monitor structures in service is driving technology in new directions. Advances in many areas including novel sensor technologies afford new opportunities in structural health monitoring. We present efforts to develop structural ...
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Journal articlePhysical review. E, Statistical, nonlinear, and soft matter physics · December 2004
We examine the Seidel aberrations of thin spherical lenses composed of media with refractive index not restricted to be positive. We find that consideration of this expanded parameter space allows for the reduction or elimination of more aberrations than i ...
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Journal articleMicrowave Journal · November 1, 2004
In this article, a medium power pseudomorphic HEMT device is used in the design of a high efficiency class-F power amplifier (PA) operating at 900 MHz. The purpose of this article is to describe the design procedure of a class-F PA with a very low drain bi ...
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Journal articlePhysical Review Letters · September 24, 2004
The stepping of the refraction interface, due to the finite unit cell size was showed by numerical simulation and by measurements on negative-index metamaterial wedge samples. The surface stepping on the metamaterial sample constitutes a grating, which cou ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · September 13, 2004
Due to the recent experimental validations of left-handed metamaterials, negative refractive index has now become recognized as a new parameter space for the electromagnetic response of materials. Because materials with negative index behave quite differen ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · September 11, 2004
An investigation of fluctuating pixels resulting from proton irradiation of an E2V Technologies CCD47-20 device is presented. The device structure, experimental set up and irradiation methodology are described, followed by a detailed analysis of radiation ...
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Journal articleJournal of High Energy Physics · September 1, 2004
We show that the recently constructed 5-dimensional supersymmetric S 1 /(Z2 × Z′2) orbifold GUT models allow an appealing explanation of the observed hierarchical structure of the quark and lepton masses and mixing angles. ...
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Journal articleScience · August 6, 2004
Recently, artificially constructed metamaterials have become of considerable interest, because these materials can exhibit electromagnetic characteristics unlike those of any conventional materials. Artificial magnetism and negative refractive index are tw ...
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Journal articleJournal of Physical Chemistry B · August 5, 2004
Silver micro- and nanocrystallites are prepared on porous Si substrates by immersion plating, and their activity toward SERS (surface-enhanced Raman scattering) is assessed. Scanning electron microscopy reveals a rough silver film containing randomly space ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · April 1, 2004
The swept charge device has been developed using CCD technology to perform photon counting X-ray spectroscopy in the 0.5-10keV band as an alternative to silicon PIN and drift diode detectors. The key benefits of the detector are large area, combined with r ...
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Journal articleReview of Scientific Instruments · April 1, 2004
The angle resolved microwave spectrometer (ARMS) provides highly reproductible automated data acquisition of microwave refraction from positive and negative refracting samples. The flexibility of the instrument allows many types of metamaterial experiments ...
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Journal articleApplied Physics Letters · March 29, 2004
The indefinite medium slab for which the permeability component along the z-axis of propagation was negative, while other permeability and permittivity tensors were positive was discussed. It was observed from simulations and transmission experiments on th ...
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Journal articleScience (New York, N.Y.) · March 2004
We show that magnetic response at terahertz frequencies can be achieved in a planar structure composed of nonmagnetic conductive resonant elements. The effect is realized over a large bandwidth and can be tuned throughout the terahertz frequency regime by ...
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Journal articlePhysical Review D - Particles, Fields, Gravitation and Cosmology · January 1, 2004
We study precision electroweak constraints on the close cousin of the littlest Higgs model, the [Formula Presented] model. We identify a near-oblique limit in which the heavy [Formula Presented] and [Formula Presented] decouple from the light fermions, and ...
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Journal articlePhysical Review E Statistical Physics Plasmas Fluids and Related Interdisciplinary Topics · January 1, 2004
We argue, in agreement with our previous work, that periodicity of the metamaterial is responsible for antiresonant behavior of the effective permittivity as well as for the negative sign of the imaginary part of an effective permittivity or permeability. ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 2004
Initial experiments on wedge samples composed of isotropic metamaterials with simultaneously negative permittivity and permeability have indicated that electromagnetic radiation can be negatively refracted. In more recently reported experiments [Phys. Rev. ...
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Journal articleIEICE Transactions on Electronics · January 1, 2004
Artificial electromagnetic structures have significantly broadened the range of wave propagation phenomena available. In particular, it has been shown that metamaterials can be constructed for which the index-of-refraction is negative over a finite band of ...
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Journal articlePhysics World · January 1, 2004
The subject of negative-index phenomena is drawing significant interest among researchers due to the emergence of a new class of artificially structured materials called metamaterials. Such materials can be engineered so that they have a much wider range o ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · January 1, 2004
We have designed, produced, and experimentally characterized 2.7 mm thick composite panels having negative refractive index between 8.4 and 9.2 GHz. The composite metamaterial is fabricated using conventional commercial multilayer circuit-board lithography ...
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Journal articlePhysics Today · January 1, 2004
The phenomenon of negative refraction is studied. This new field has generated great enthusiasm but also controversy, yet even the controversies have had the positive effect that key concepts have been critically scrutinized in the past 18 months. Many gro ...
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Journal articleIEEE Antennas and Propagation Society AP S International Symposium Digest · January 1, 2004
Surface plasmons (SPs) are interface waves very similar to Zenneck waves but existing only at optical frequencies where metals exhibit a negative permittivity. The availability of novel structured metamaterials with tailorable positive/negative constitutiv ...
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Journal articlePhysical Review E Statistical Nonlinear and Soft Matter Physics · December 1, 2003
The numerical analysis of the electromagnetic response of two metamaterials which include an array of split ring resonators (SRR) and an array of thin metallic cut wires was presented. It was found that the effective parameters of these systems exhibit res ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · December 1, 2003
Nano gold particles interact strongly with visible light to excite the collaborative oscillation of conductive electrons within nano particles resulting in a surface plasmon resonance which makes them useful for various applications including bio-labeling. ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · December 1, 2003
We present a detailed description of the apparatus and techniques that we have utilized in our experimental study of individual plasmon resonant nanoparticles, along with a brief description of some major results. The apparatus consists of a spectroscopic ...
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Journal articleMicrowave and Optical Technology Letters · November 5, 2003
A novel structure of broadband microstrip antennas, termed the SGMFP antenna, is proposed. It is consisted of a slot in the ground plane, a microstrip feedline supported on a substrate, a foam layer, and a patch. It can achieve broad bandwidth and high pol ...
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Journal articleIEEE Microwave and Wireless Components Letters · September 1, 2003
Indirect holography provides a quick and inexpensive three-dimensional (3-D) imaging technique at optical frequencies which has not been directly adapted to microwave imaging. This letter describes a technique whereby a radiated offset reference plane wave ...
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Journal articleNano Letters · August 1, 2003
The collaborative oscillation of conductive electrons in metal nanoparticles results in a surface plasmon resonance that makes them useful for various applications including biolabeling. We investigate the coupling between pairs of elliptical metal particl ...
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Journal articleApplied Physics Letters · July 7, 2003
Terahertz plasmonic high pass filter was studied. The sharp change of reflection and transmission of electromagnetic waves at plasma frequency made the structure a high pass filter. Fourier transform infrared spectroscopy was used to characterize the refle ...
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Journal articleNuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms · June 1, 2003
The University of Tübingen 3.5 MeV Van de Graaff accelerator facility was used to investigate the effect of low-energy protons on the performance of the European Photon Imaging Camera, metal-oxide-semiconductor, charge-coupled devices (CCDs). Two CCDs were ...
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Journal articleApplied Physics Letters · April 7, 2003
The construction of bandpass spatial, low pass and high pass filters was discussed. Bilayers of media with indefinite permittivity and permeability tensors were used for the construction. The filters formed had sharp adjustable roll-offs and could operate ...
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Journal articleNano Letters · April 1, 2003
We present an experimental optical darkfield microscope study of the dependence of the plasmon resonance spectrum of individual silver nanoparticles on the local index of refraction. We systematically characterize the position of the resonance peaks associ ...
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Journal articleApplied Physics Letters · March 10, 2003
Limitations on subdiffraction imaging with a negative refractive index slab was studied. The planar geometry allowed a straight forward analysis to be implemented. The fields from an arbitray electromagnetic source were expanded in a Fourier series over ho ...
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Journal articlePhysical Review E Statistical Physics Plasmas Fluids and Related Interdisciplinary Topics · January 1, 2003
We present a numerical study of the electromagnetic response of the metamaterial elements that are used to construct materials with negative refractive index. For an array of split ring resonators (SRR) we find that the resonant behavior of the effective m ...
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Journal articlePhysics Education · January 1, 2003
�‘Voyager’ is an educational card game involving scientific satellites, developed for use in schools with children aged 9 to 13 years. The idea of the game is to improve pupils’ knowledge about the large number of scientific satellites there are in space i ...
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Journal articlePhysics World · January 1, 2003
Recent experiments that demonstrated the negative refraction of light were presented. The refraction at the interface between a positive-index material and a negative index material teared the wave apart, leaving no single negatively refracted wave. The re ...
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Journal articlePhysical Review Letters · January 1, 2003
We study the behavior of wave propagation in materials for which not all of the principal elements of the permeability and permittivity tensors have the same sign. We find that a wide variety of effects can be realized in such media, including negative ref ...
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Journal articleOptics Express · January 1, 2003
We study numerically the electromagnetic scattering properties of structures with negative indices of refraction. To perform this analysis, we utilize a commercial finite-element based electromagnetic solver (HFSS, Ansoft), in which a negative index materi ...
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Journal articlePhysical Review D · January 1, 2003
In warped supersymmetric grand unification, XY gauge particles appear near the TeV scale along with Kaluza-Klein towers of the standard model gauge fields. In spite of this exotic low-energy physics, the successful gauge coupling unification prediction of ...
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Journal articlePhysical Review D Particles Fields Gravitation and Cosmology · January 1, 2003
We construct a realistic theory of grand unification in [Formula Presented] truncated by branes, in which the unified gauge symmetry is broken by boundary conditions and the electroweak scale is generated by the AdS warp factor. We show that the theory pre ...
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Journal articleAmerican Society of Mechanical Engineers Micro Electromechanical Systems Division Publication MEMS · January 1, 2003
Micro-structured materials, which contain engineered sub-wavelength components, can be designed to have positive or negative ε and μ at desired frequency. In this paper, we demonstrate a high pass Terahertz (THz) filter which utilizes the lowered plasma fr ...
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Journal articleNuclear Physics B Proceedings Supplements · January 1, 2003
The DAMA annual modulation signature, interpreted as evidence for a spin-independent WIMP coupling, seems in conflict with null results from CDMS. However, in models of "inelastic dark matter", the experiments are compatible. Inelastic dark matter can aris ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · December 1, 2002
The large scattering cross section of plasmon resonant gold and silver nanoparticles functionalized with the appropriate ligand allows for sensitive and specific detection of nucleic acids and proteins. By varying the size, shape, and material morphology p ...
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Journal articlePhysical Review D · December 1, 2002
We construct supersymmetric models of SO(10) unification in which the gauge symmetry is broken by orbifold compactification. We find that using boundary conditions to break the gauge symmetry down to SU(3) C⊗ SU(2) L ⊗U(1) Y⊗U(1) X without leaving unwanted ...
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Journal articleApplied Physics Letters · October 7, 2002
We show that a modulated Gaussian beam undergoes negative refraction at the interface between a positive and negative refractive index material. While the refraction of the beam is clearly negative, the modulation interference fronts are not normal to the ...
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Journal articleNuclear Physics B · September 9, 2002
The electroweak Higgs doublets are identified as components of a vector multiplet in a higher-dimensional supersymmetric field theory. We construct a minimal model in 6D where the electroweak SU (2) ⊗ U (1) gauge group is extended to SU(3), and unified 6D ...
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Journal articleJournal of Modern Optics · August 15, 2002
We extend the ideas of the perfect lens recently proposed [J.B. Pendry, Phys. Rev. Lett. 85, 3966 (2000)] to an alternative structure. We show that a slab of a medium with negative refractive index bounded by media of different positive refractive index al ...
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Journal articleJournal of Applied Physics · June 1, 2002
We present a method of fabricating single crystal silver nanowires based on the electroless deposition of silver into the pores of the polycarbonate membranes by the metal amplification process. A gold film on one side of the nanoporous membrane is used as ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · May 15, 2002
We analyze the reflection and transmission coefficients calculated from transfer matrix simulations on finite lengths of electromagnetic metamaterials, to determine the effective permittivity (ε) and permeability (μ). We perform this analysis on structures ...
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Journal articleNano Letters · May 1, 2002
We present an experimental study of the polarization-dependent scattering of light from homogeneous and multisegment silver, gold, and nickel nanowires. The metallic nanowires are prepared within a polycarbonate membrane template by a combination of electr ...
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Journal articleNuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · April 21, 2002
The effect of non-ionising energy loss of protons in charge-coupled devices is to displace silicon atoms and any dopant materials present from their lattice positions to form lattice defects which in turn can trap electrons (IEEE Trans. Nucl. Sci. NS-40 (1 ...
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Journal articleJournal of Chemical Physics · April 15, 2002
The effect of shape of individual silver colloidal nanoparticle on surface plasmon resonance was investigated by an optical detection technique combined with high resolution transmission electron microscopy (TEM). The geometrical shape of nanoparticle had ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · January 1, 2002
We analyze the reflection and transmission coefficients calculated from transfer matrix simulations on finite lengths of electromagnetic metamaterials, to determine the effective permittivity (ε) and permeability (µ). We perform this analysis on structures ...
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Journal articlePhysical Review D Particles Fields Gravitation and Cosmology · January 1, 2002
We construct an (Formula presented) non-linear sigma model in which the Higgs bosons arise as pseudo Goldstone bosons. There are two Higgs doublets whose masses have no one-loop quadratic sensitivity to the cutoff of the effective theory, which can be at a ...
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Journal articlePhysical Review D - Particles, Fields, Gravitation and Cosmology · January 1, 2002
We study fermion localization in gauge theory space. We consider four-dimensional product gauge groups in which light chiral fermions transform under different gauge factors of the product group. This construction provides a suppression of higher dimension ...
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Journal articlePhysical Review B Condensed Matter and Materials Physics · December 15, 2001
We investigate numerically the spectrum of plasmon resonances for metallic nanowires with a nonregular Z, cross section, in the 20-50 nm range. We first consider the resonance spectra corresponding to nanowires whose cross sections form different simplexes ...
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Journal articlePhysical Review D · December 1, 2001
An alternative to the conventional seesaw mechanism is proposed to explain the origin of small neutrino masses in supersymmetric theories. The masses and couplings of the right-handed neutrino field are suppressed by supersymmetry breaking, in a way simila ...
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Journal articleJournal of Applied Physics · November 15, 2001
Using numerical simulation techniques, the transmission and reflection coefficients, or S parameters, for left-handed metamaterials are calculated. Metamaterials consist of a lattice of conducting, nonmagnetic elements that can be described by an effective ...
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Journal articleNuclear Physics B · October 8, 2001
We present a five-dimensional supersymmetric SU(5) theory in which the gauge symmetry is broken maximally (i.e., at the 5D Planck scale M*) on the same 4D brane where chiral matter is localized. Masses of the lightest Kaluza-Klein modes for the ...
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Journal articleNuclear Physics B · July 2, 2001
A new physical origin for electroweak symmetry breaking is proposed, involving compact spatial dimensions of scale 1/R≈1 TeV. The higher-dimensional theory is supersymmetric, and hence requires the top-quark Yukawa coupling to be localized on some "Yukawa ...
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Journal articleChemical Physics Letters · June 15, 2001
We investigate numerically the plasmon resonances of 10-50 nm nanowires with a non-elliptical section. Such wires have a much more complex behavior than elliptical wires and their resonances span a larger frequency range. The field distribution at the surf ...
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Journal articleNuclear Fusion · May 1, 2001
A characterization is presented of Mo sources ΓMo, core Mo content NMo and their dependences on the Alcator C-Mod operational regimes. The primary impurity source locations are the divertor, the inner wall and the ICRF antenna limiter ...
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Journal articleScience (New York, N.Y.) · April 2001
We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of ...
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Journal articleJournal of microscopy · April 2001
We study numerically two-dimensional nanoparticles with a non-regular shape and demonstrate that these particles can support many more plasmon resonances than a particle with a regular shape (e.g. an ellipse). The electric field distributions associated wi ...
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Journal articleApplied Physics Letters · January 22, 2001
We present experimental data, numerical simulations, and analytical transfer-matrix calculations for a two-dimensionally isotropic, left-handed metamaterial (LHM) at X-band microwave frequencies. A LHM is one that has a frequency band with simultaneously n ...
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Journal articleJournal of Nuclear Materials · January 1, 2001
We present a characterization of molybdenum sources, ΓMo, core Mo content, NMo, and their dependencies on Alcator C-Mod operational regimes. This includes sources from the divertor, the inner wall and the ICRF antenna limiters. We als ...
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Journal articlePhysical Review Letters · 2001
An overview is given on the results of searches for B decays to the charmless two-body final states B
+→wπ
+, B
+→wK
+, B
+→η'π
...
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Journal articlePhysical Review Letters · 2001
An attempt was made to observe B decays to φK
+, φK
0, φK
*+, and φK
*0 with significances, including systematic uncertainties, of greater than four standard de ...
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Journal articlePhysical Review D Particles Fields Gravitation and Cosmology · January 1, 2001
Many observations suggest that much of the matter of the universe is nonbaryonic. Recently, the DAMA NaI dark matter direct detection experiment reported an annual modulation in their event rate consistent with a WIMP relic. However, the Cryogenic Dark Mat ...
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Journal articlePhysical Review D · January 1, 2001
The supersymmetric "shining" of free massive chiral superficiels in extra dimensions from a distant source brane can trigger exponentially small supersymmetry breaking on our brane of order e~27rR, where R is the radius of the extra dimensions. This supers ...
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Journal articleNew Journal of Physics · November 3, 2000
We study the plasmon resonances for small two-dimensional silver particles (nanowires) with elliptical or triangular shapes in the 20 nm size range. While the elliptical particle has only two resonances, a well known fact, we demonstrate that the triangula ...
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Journal articleApplied Physics Letters · October 2, 2000
Recently, an electromagnetic metamaterial was fabricated and demonstrated to exhibit a "left-handed" (LH) propagation band at microwave frequencies. A LH metamaterial is one characterized by material constants - the permeability and permittivity - which ar ...
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Journal articlePhysical Review Letters · October 2, 2000
The presence of negative refractive index in steady-state problems was explored. It was observed that this index leads to unusual and unexplored phenomena in wave propagation. A formalism was derived that can be applied to time dependent currents and pulse ...
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Journal articlePhysical review letters · May 2000
We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeab ...
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Journal articleProceedings of the National Academy of Sciences of the United States of America · February 2000
We introduce and demonstrate the use of colloidal silver plasmon-resonant particles (PRPs) as optical reporters in typical biological assays. PRPs are ultrabright, nanosized optical scatterers, which scatter light elastically and can be prepared with a sca ...
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Journal articlePhysical Review D - Particles, Fields, Gravitation and Cosmology · January 1, 2000
In theories with (sets of) two large extra dimensions and supersymmetry in the bulk, the presence of non-supersymmetric brane defects naturally induces a logarithmic potential for the volume of the transverse dimensions. Since the logarithm of the volume r ...
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Journal articleOptics Express · January 1, 2000
We study the plasmon resonances of 10-100(nm) two-dimensional metal particles with a non-regular shape. Movies illustrate the spectral response of such particles in the optical range. Contrary to particles with a simple shape (cylinder, ellipse) non-regula ...
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Journal articleConference on Lasers and Electro Optics Europe Technical Digest · January 1, 2000
A single split ring resonator (SRR) was fabricated lithographically and its accompanying resonance curve is shown to determine if periodic arrays of SRRs can have a resonantly enhanced effective permeability displaying frequency regions with large positive ...
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Journal articleProceedings of the IEEE Particle Accelerator Conference · December 1, 1999
In previous work we have proposed utilizing Photonic Band Gap (PBG) structures as a new class of high-energy, high-intensity accelerator cavities. We have completed extensive MAFIA numerical calculations of multicell PBG structures, with each cell consisti ...
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Journal articleApplied Physics Letters · September 6, 1999
A localized surface plasmon resonance is demonstrated at microwave frequencies. The plasmon structure is based on the assumption that the effective dielectric constant of the loop wire is due to the self-inductance of the constituent wire. The plasmon stru ...
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Journal articleJournal of Clinical Ligand Assay · June 1, 1999
An introduction to the utilization of plasmon resonant particles as optical labels for diverse biological applications is presented. Plasmon resonant particles (PRP(TM)) (Seashell Technology LLC, La Jolla, CA) are sub- micron (40-100 nanometer), ultra-brig ...
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Journal articlePhysical Review D - Particles, Fields, Gravitation and Cosmology · June 1, 1999
In theories with three light neutrinos, certain simplicity assumptions allow the construction of a complete list of leading order lepton mass matrices. These matrices are consistent with mτ≠0,Δm122≪Δm232,θ23∼O(1) and θ13=0, as suggested by measurements of ...
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Journal articlePhysical Review D Particles Fields Gravitation and Cosmology · May 10, 1999
In theories with three light neutrinos, certain simplicity assumptions allow the construction of a complete list of leading order lepton mass matrices. These matrices are consistent with (Formula presented) and (Formula presented) as suggested by measureme ...
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Journal articlePhysical Review Letters · January 11, 1999
We investigate the properties of photonic hand gap structures of finite size and arbitrary geometry using the density of states deduced from scattering calculations. We first demonstrate this procedure on a finite 2D array of cylinders and then study at op ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · January 1, 1999
A control strategy based on the relative position of the armature and body, and an actuator which has the necessary features to take advantage of this approach, is developed. This strategy provides a modular approach to vibration isolation because it acts ...
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Journal articlePhysical Review D Particles Fields Gravitation and Cosmology · January 1, 1999
In theories with large extra dimensions, constraints from cosmology lead to nontrivial lower bounds on the gravitational scale M, corresponding to upper bounds on the radii of the compact extra dimensions. These constraints are especially relevant to the c ...
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Journal articleJournal of High Energy Physics · January 1, 1998
Motivated by recent results from SuperKamiokande, we study both solar and atmospheric neutrino fluxes in the context of oscillations of the three known neutrinos. We aim at a global view which identifies the various possibilities, rather than attempting th ...
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Journal articleMicrowave and Optical Technology Letters · April 5, 1997
The nonresonant-length backfire bifilar helix is often used as a vehicle satcom antenna, as it has a circularly polarized conical beam with azimuthal symmetry. Some antenna configurations, however, exhibit poor back-lobe levels. It is shown that radiation ...
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Journal articleInternational Journal of Thermophysics · January 1, 1997
We have measured the thermal expansion of the three principal orthogonal directions of an E-glass/vinyl ester structural composite from liquid helium temperature, 4.2 K, to room temperature, 293 K. The linear thermal expansion at 4.2 K ranged from -0.23 to ...
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Journal articleInternational Journal of Thermophysics · January 1, 1997
In the early 1980s, an international round-robin was held in which the apparent thermal conductivity of specimens of fibrous glass insulation board was measured by users of guarded hot plates (GHPs) and heat-flow meters (HFMs). The round-robin was performe ...
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Journal articleIEEE Transactions on Magnetics · December 1, 1996
The magnetostatic and frequency response characteristics of the unshielded magnetoresistive (UMR) head have been previously calculated by means of a numerical simulation which ultilized the principle of reciprocity to reduce the computational task of solvi ...
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Journal articleIEEE Transactions on Magnetics · December 1, 1996
We present analytic procedures for calculating the magnetostatic and response functions of magnetoresistive (MR) recording heads. To apply these methods we make several simplifying approximations, which have been found to be valid for typical recording hea ...
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Journal articleMicrowave and Optical Technology Letters · June 20, 1996
The design of a small, low-cost anechoic chamber well suited to the teaching of antenna theory and measurement techniques is described. The chamber design allows for dismantling, relocation, and reassembly when required. Its performance in the range 18-30 ...
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Journal articleJournal of Applied Physics · January 15, 1996
Dipole radiation in a two-dimensional periodic dielectric structure is studied both theoretically and experimentally in this article. For the two-dimensional square lattice structure with dielectric cylinders, the emission power of an electric dipole in th ...
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Journal articleIEEE MTT S International Microwave Symposium Digest · January 1, 1996
We study a new type of waveguide structures - two-dimensional photonic crystals sandwiched between two metal conductors. In the structures, not only the electromagnetic propagation, but also the radiation spectra can be controlled. Radiation from microwave ...
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Journal articleProceedings of the IEEE Particle Accelerator Conference · December 1, 1995
An 18-MeV, 433-MHz linac capable of operating at 25% RF duty factor (DF) is being commissioned for FEL applications. Comprising a two-cell RF photocathode injector followed by four new multicell cavities, the linac is an extension of the photoinjector whic ...
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Journal articleComputer Physics Communications · May 2, 1995
MAGIC is a user-configurable code that solves Maxwell's equations together with Lorentz particle motion. A variety of 2D, finite-difference electromagnetic algorithms and 3D particle-in-cell algorithms may be combined in problem-specific ways to provide fa ...
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Journal articleCan. J. Electr. Comput. Eng. (Canada) · 1995
Given the growing number of interactive nonlinear loads in power distribution systems, some techniques to monitor the spread of harmonics through the power system need to be developed. This paper examines the nature of harmonics in a naval power distributi ...
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Journal articleInt. J. Mini Microcomput. (USA) · 1995
A circuit-switched shared-memory multiprocessor based on the 2D spanning bus hypercube is described. This design eliminates most of the processing overhead attributed to message passing systems. Circuit switching allows the sender to transfer directly into ...
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Journal articleApplied Physics Letters · December 1, 1994
We demonstrate, by both microwave experiments and numerical simulation, that a two-dimensional lattice of metal cylinders can form a complete photonic band-gap (PBG) structure. The band structure exhibits a single broad PBG extending from zero frequency to ...
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Journal articleIEEE Transactions on Magnetics · January 1, 1994
A beam emission spectroscopy (BES) system has been installed on the National Spherical Torus Experiment (NSTX) to study ion gyroscale ?uctuations. The BES system measures Dαemission from a deuterium neutral heating beam. The system includes two ...
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Journal articleJ. Mod. Opt. (UK) · 1994
Structures arranged so as to exhibit a complete photonic bandgap (PGB) have been proposed for a variety of technological applications. McCall et al. have reported an experimental and numerical investigation of microwave propagation in a two-dimensional arr ...
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Journal articleProceedings of the IEEE Particle Accelerator Conference · December 1, 1993
We have proposed that a new type of microwave resonator, based on Photonic Band Gap (PBG) structures, may be particularly useful for high energy accelerators. We provide an explanation of the PBG concept and present data which illustrate some of the specia ...
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Journal articleJournal of the Optical Society of America B Optical Physics · January 1, 1993
We present an experimental and numerical study of electromagnetic wave propagation in one-dimensional (D) and two-dimensional (2D) systems composed of periodic arrays of dielectric scatterers. We demonstrate that there are regions of frequency for which th ...
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Journal articleIEEE Transactions on Magnetics · January 1, 1992
A recently proposed dual magnetoresistive (DMR) reproduce head, consisting of two identical, adjacent MR stripes separated by a nonmagnetic spacer and connected electrically in parallel, was shown to have potential in very high density magnetic recording a ...
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Journal articlePhysical Review Letters · January 1, 1991
We have calculated and measured the properties of X-band microwaves propagating in a 2D array of low-loss high-dielectric-constant cylinders. Transmission bands and photonic band gaps are conclusively identified in excellent agreement with the theoretical ...
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Journal articleProceedings of SPIE the International Society for Optical Engineering · April 3, 1981
In recent years, the Air Force Geophysics Laboratory has flown several rocketborne experiments with cryogenic interferometers to measure natural and induced infrared atmospheric emissions. AFGL is currently developing two separate shuttle payloads based on ...
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