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Willie John Padilla

Professor in the Department of Electrical and Computer Engineering
Electrical and Computer Engineering

Selected Publications


Symmetry-Broken High-Q Terahertz Quasi-Bound States in the Continuum

Journal Article ACS Photonics · May 15, 2024 Electromagnetic metasurfaces possess unique scattering effects that enable wavefront control. Relatively recently, metasurfaces have been shown to support an unconventional phenomenon known as bound states in continuum (BIC) modes. BICs enable the confinem ... Full text Cite

Transfer learning for metamaterial design and simulation

Journal Article Nanophotonics · May 3, 2024 We demonstrate transfer learning as a tool to improve the efficacy of training deep learning models based on residual neural networks (ResNets). Specifically, we examine its use for study of multi-scale electrically large metasurface arrays under open boun ... Full text Cite

Extremely Thin Perfect Absorber by Generalized Multipole Bianisotropic Effect

Journal Article Advanced Optical Materials · March 5, 2024 Symmetry breaking plays a crucial role in understanding the fundamental physics underlying numerous physical phenomena, including the electromagnetic response in resonators, giving rise to intriguing effects such as directional light scattering, supercavit ... Full text Cite

Machine Learning for Engineering Meta-Atoms with Tailored Multipolar Resonances

Journal Article Laser and Photonics Reviews · January 1, 2024 In the rapidly developing field of nanophotonics, machine learning (ML) methods facilitate the multi-parameter optimization processes and serve as a valuable technique in tackling inverse design challenges by predicting nanostructure designs that satisfy s ... Full text Cite

Fundamental absorption bandwidth to thickness limit for transparent homogeneous layers

Journal Article Nanophotonics · January 1, 2024 Past work has considered the analytic properties of the reflection coefficient for a metal-backed slab. The primary result established a fundamental relationship for the minimal layer thickness to bandwidth ratio achievable for an absorber. There has yet t ... Full text Cite

The 2023 terahertz science and technology roadmap

Journal Article Journal of Physics D: Applied Physics · June 1, 2023 Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz-∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have pr ... Full text Cite

Resonant leaky modes in all-dielectric metasystems: Fundamentals and applications

Journal Article Physics Reports · April 5, 2023 All-dielectric metamaterials and metasurfaces have been demonstrated as ideal platforms to manipulate electromagnetic waves and enhance light–matter interaction. Analogous to guided modes in a dielectric waveguide, high refractive index dielectric metasurf ... Full text Cite

Informed Deep Learning in Metamaterials

Conference 2023 International Applied Computational Electromagnetics Society Symposium, ACES-Monterey 2023 · January 1, 2023 Deep neural networks have demonstrated capability to solve challenging forward and inverse problems in electromagnetic metamaterials. However, they often require large quantities of data to achieve a given level of accuracy, which poses a data bottleneck i ... Full text Cite

Multipolar Resonance Engineering Using Machine Learning

Conference International Conference on Metamaterials, Photonic Crystals and Plasmonics · January 1, 2023 We developed machine learning models to predict the multipolar resonances and electric field distributions of all-dielectric meta-atoms. Machine learning method is also used for inverse designing meta-atoms based on the desired multipolar resonances. ... Cite

Forward and Inverse Design of Artificial Electromagnetic Materials

Chapter · January 1, 2023 Deep learning, and deep neural networks (DNNs) in particular, has recently demonstrated impressive results for the design of artificial electromagnetic materials (AEMs). In this context AEMs are materials whose properties derive primarily from their struct ... Full text Cite

Normalization flows for designing metasurfaces

Conference International Conference on Metamaterials, Photonic Crystals and Plasmonics · January 1, 2023 Training data are very expensive for metasurface designs using deep-learning based methods. To achieve data efficiency, we introduced normalization flows to inversely design metasurfaces through learning the probabilistic distribution of the data. To explo ... Cite

Mie Resonance-based Meta-atom Design with Machine Learning Method

Conference 2023 Conference on Lasers and Electro-Optics, CLEO 2023 · January 1, 2023 Forward prediction machine learning models were developed to predict the scattering behaviors and electromagnetic field of meta-atoms, while an inverse design model was built for reconstructing meta-atoms under the guidance of multipole expansion theory. ... Cite

Transparent phase dielectric metasurfaces

Chapter · January 1, 2023 This chapter provides an overview of transparent phase dielectric metasurfaces, a rapidly growing field that has potential to revolutionize optical materials and devices. The chapter starts with an introduction to simple harmonic oscillator and coupled osc ... Full text Cite

Mie Resonance-based Meta-atom Design with Machine Learning Method

Conference CLEO: Science and Innovations, CLEO:S and I 2023 · January 1, 2023 Forward prediction machine learning models were developed to predict the scattering behaviors and electromagnetic field of meta-atoms, while an inverse design model was built for reconstructing meta-atoms under the guidance of multipole expansion theory. ... Full text Cite

Deep inverse photonic design: A tutorial

Journal Article Photonics and Nanostructures - Fundamentals and Applications · December 1, 2022 Deep learning (DL) has been used to design deep neural networks (DNNs) which have recently been applied to solving inverse problems in artificial electromagnetic materials (AEMs). Although inverse problems are often ill-posed, and therefore are difficult t ... Full text Cite

Metasurfaces for photonic devices

Journal Article Journal of Applied Physics · November 21, 2022 Full text Cite

Active and tunable nanophotonic metamaterials

Journal Article Nanophotonics · September 2, 2022 Metamaterials enable subwavelength tailoring of light-matter interactions, driving fundamental discoveries which fuel novel applications in areas ranging from compressed sensing to quantum engineering. Importantly, the metallic and dielectric resonators fr ... Full text Cite

Pyroelectric metamaterial millimeter-wave detector

Journal Article Applied Physics Letters · July 11, 2022 We present experimental demonstration of a multi-functional metamaterial absorber, which operates as an efficient detector of millimeter wave radiation at room temperature. Intimate integration of a pyroelectric crystal directly within the metamaterial uni ... Full text Cite

Learning the Physics of All-Dielectric Metamaterials with Deep Lorentz Neural Networks

Journal Article Advanced Optical Materials · July 1, 2022 Deep neural networks (DNNs) have shown marked achievements across numerous research and commercial settings. Part of their success is due to their ability to “learn” internal representations of the input (x) that are ideal to attain an accurate approximati ... Full text Cite

Inverse deep learning methods and benchmarks for artificial electromagnetic material design.

Journal Article Nanoscale · March 2022 In this work we investigate the use of deep inverse models (DIMs) for designing artificial electromagnetic materials (AEMs) - such as metamaterials, photonic crystals, and plasmonics - to achieve some desired scattering properties (e.g., transmissio ... Full text Cite

Symmetry-Broken High-Q Terahertz Quasi-Bound States in the Continuum

Journal Article ACS Photonics · May 15, 2024 Electromagnetic metasurfaces possess unique scattering effects that enable wavefront control. Relatively recently, metasurfaces have been shown to support an unconventional phenomenon known as bound states in continuum (BIC) modes. BICs enable the confinem ... Full text Cite

Transfer learning for metamaterial design and simulation

Journal Article Nanophotonics · May 3, 2024 We demonstrate transfer learning as a tool to improve the efficacy of training deep learning models based on residual neural networks (ResNets). Specifically, we examine its use for study of multi-scale electrically large metasurface arrays under open boun ... Full text Cite

Extremely Thin Perfect Absorber by Generalized Multipole Bianisotropic Effect

Journal Article Advanced Optical Materials · March 5, 2024 Symmetry breaking plays a crucial role in understanding the fundamental physics underlying numerous physical phenomena, including the electromagnetic response in resonators, giving rise to intriguing effects such as directional light scattering, supercavit ... Full text Cite

Machine Learning for Engineering Meta-Atoms with Tailored Multipolar Resonances

Journal Article Laser and Photonics Reviews · January 1, 2024 In the rapidly developing field of nanophotonics, machine learning (ML) methods facilitate the multi-parameter optimization processes and serve as a valuable technique in tackling inverse design challenges by predicting nanostructure designs that satisfy s ... Full text Cite

Fundamental absorption bandwidth to thickness limit for transparent homogeneous layers

Journal Article Nanophotonics · January 1, 2024 Past work has considered the analytic properties of the reflection coefficient for a metal-backed slab. The primary result established a fundamental relationship for the minimal layer thickness to bandwidth ratio achievable for an absorber. There has yet t ... Full text Cite

The 2023 terahertz science and technology roadmap

Journal Article Journal of Physics D: Applied Physics · June 1, 2023 Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz-∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have pr ... Full text Cite

Resonant leaky modes in all-dielectric metasystems: Fundamentals and applications

Journal Article Physics Reports · April 5, 2023 All-dielectric metamaterials and metasurfaces have been demonstrated as ideal platforms to manipulate electromagnetic waves and enhance light–matter interaction. Analogous to guided modes in a dielectric waveguide, high refractive index dielectric metasurf ... Full text Cite

Informed Deep Learning in Metamaterials

Conference 2023 International Applied Computational Electromagnetics Society Symposium, ACES-Monterey 2023 · January 1, 2023 Deep neural networks have demonstrated capability to solve challenging forward and inverse problems in electromagnetic metamaterials. However, they often require large quantities of data to achieve a given level of accuracy, which poses a data bottleneck i ... Full text Cite

Multipolar Resonance Engineering Using Machine Learning

Conference International Conference on Metamaterials, Photonic Crystals and Plasmonics · January 1, 2023 We developed machine learning models to predict the multipolar resonances and electric field distributions of all-dielectric meta-atoms. Machine learning method is also used for inverse designing meta-atoms based on the desired multipolar resonances. ... Cite

Forward and Inverse Design of Artificial Electromagnetic Materials

Chapter · January 1, 2023 Deep learning, and deep neural networks (DNNs) in particular, has recently demonstrated impressive results for the design of artificial electromagnetic materials (AEMs). In this context AEMs are materials whose properties derive primarily from their struct ... Full text Cite

Normalization flows for designing metasurfaces

Conference International Conference on Metamaterials, Photonic Crystals and Plasmonics · January 1, 2023 Training data are very expensive for metasurface designs using deep-learning based methods. To achieve data efficiency, we introduced normalization flows to inversely design metasurfaces through learning the probabilistic distribution of the data. To explo ... Cite

Mie Resonance-based Meta-atom Design with Machine Learning Method

Conference 2023 Conference on Lasers and Electro-Optics, CLEO 2023 · January 1, 2023 Forward prediction machine learning models were developed to predict the scattering behaviors and electromagnetic field of meta-atoms, while an inverse design model was built for reconstructing meta-atoms under the guidance of multipole expansion theory. ... Cite

Transparent phase dielectric metasurfaces

Chapter · January 1, 2023 This chapter provides an overview of transparent phase dielectric metasurfaces, a rapidly growing field that has potential to revolutionize optical materials and devices. The chapter starts with an introduction to simple harmonic oscillator and coupled osc ... Full text Cite

Mie Resonance-based Meta-atom Design with Machine Learning Method

Conference CLEO: Science and Innovations, CLEO:S and I 2023 · January 1, 2023 Forward prediction machine learning models were developed to predict the scattering behaviors and electromagnetic field of meta-atoms, while an inverse design model was built for reconstructing meta-atoms under the guidance of multipole expansion theory. ... Full text Cite

Deep inverse photonic design: A tutorial

Journal Article Photonics and Nanostructures - Fundamentals and Applications · December 1, 2022 Deep learning (DL) has been used to design deep neural networks (DNNs) which have recently been applied to solving inverse problems in artificial electromagnetic materials (AEMs). Although inverse problems are often ill-posed, and therefore are difficult t ... Full text Cite

Metasurfaces for photonic devices

Journal Article Journal of Applied Physics · November 21, 2022 Full text Cite

Active and tunable nanophotonic metamaterials

Journal Article Nanophotonics · September 2, 2022 Metamaterials enable subwavelength tailoring of light-matter interactions, driving fundamental discoveries which fuel novel applications in areas ranging from compressed sensing to quantum engineering. Importantly, the metallic and dielectric resonators fr ... Full text Cite

Pyroelectric metamaterial millimeter-wave detector

Journal Article Applied Physics Letters · July 11, 2022 We present experimental demonstration of a multi-functional metamaterial absorber, which operates as an efficient detector of millimeter wave radiation at room temperature. Intimate integration of a pyroelectric crystal directly within the metamaterial uni ... Full text Cite

Learning the Physics of All-Dielectric Metamaterials with Deep Lorentz Neural Networks

Journal Article Advanced Optical Materials · July 1, 2022 Deep neural networks (DNNs) have shown marked achievements across numerous research and commercial settings. Part of their success is due to their ability to “learn” internal representations of the input (x) that are ideal to attain an accurate approximati ... Full text Cite

Inverse deep learning methods and benchmarks for artificial electromagnetic material design.

Journal Article Nanoscale · March 2022 In this work we investigate the use of deep inverse models (DIMs) for designing artificial electromagnetic materials (AEMs) - such as metamaterials, photonic crystals, and plasmonics - to achieve some desired scattering properties (e.g., transmissio ... Full text Cite

Imaging with metamaterials

Journal Article Nature Reviews Physics · February 1, 2022 Metamaterials enable precise tailoring of light–matter interactions at the subwavelength scale, permitting access to the full range of electromagnetic responses encoded in Maxwell’s equations and operating across a huge swath of the electromagnetic spectru ... Full text Cite

Planar Metamaterial Absorbers for Calibration of Microwave Radiometers for Atmospheric Remote Sensing

Conference International Geoscience and Remote Sensing Symposium (IGARSS) · January 1, 2022 In this work, we present metamaterial-based microwave absorbers fabricated on organic-based printed circuit boards as promising alternatives to traditional, bulky microwave absorbers for the calibration of microwave radiometers for atmospheric remote sensi ... Full text Cite

BLASCHKE PRODUCT NEURAL NETWORK (BPNN): A PHYSICS-INFUSED NEURAL NETWORK FOR PHASE RETRIEVAL OF MEROMORPHIC FUNCTIONS

Conference ICLR 2022 - 10th International Conference on Learning Representations · January 1, 2022 Numerous physical systems are described by ordinary or partial differential equations whose solutions are given by holomorphic or meromorphic functions in the complex domain. In many cases, only the magnitude of these functions are observed on various poin ... Cite

Normalizing Flows for Efficient Inverse Design of Thermophotovoltaic Emitters

Journal Article ACS Photonics · January 1, 2022 Metasurfaces have shown flexibility in realizing various functionalities via shaping the geometry on the subwavelength scale. However, with increased design complexity, the flexibility makes the traditional paradigm based on expert knowledge less effective ... Full text Cite

Deep Learning Metamaterials

Conference International Conference on Metamaterials, Photonic Crystals and Plasmonics · January 1, 2022 We discuss the use and impact of deep learning on metamaterials and metasurfaces, including both forward and inverse design. We show inverse results on three benchmark datasets and discuss the future of this exciting field.. ... Cite

Mapping active strain using terahertz metamaterial laminates

Journal Article APL Photonics · November 1, 2021 The ability to image strain fields in composite materials is an indispensable necessity for structural health monitoring. Embedded electromagnetic metamaterials sensitive to applied stresses and operating in the terahertz regime have been proposed as a sol ... Full text Cite

Deep Learning the Electromagnetic Properties of Metamaterials—A Comprehensive Review

Journal Article Advanced Functional Materials · August 1, 2021 Deep neural networks (DNNs) are empirically derived systems that have transformed traditional research methods, and are driving scientific discovery. Artificial electromagnetic materials (AEMs)—including electromagnetic metamaterials, photonic crystals, an ... Full text Cite

A Triple-Mode Midinfrared Modulator for Radiative Heat Management of Objects with Various Emissivity.

Journal Article Nano letters · May 2021 Thermal management is ubiquitous in the modern world and indispensable for a sustainable future. Radiative heat management provides unique advantages because the heat transfer can be controlled by the surface. However, different object emissivities require ... Full text Cite

A Triple-Mode Mid-infrared Modulator for All-Surface Radiative Thermal Management

Conference 2021 Conference on Lasers and Electro-Optics, CLEO 2021 - Proceedings · May 1, 2021 We demonstrate a mid-infrared modulator that can switch among reflectance, emittance, and transmittance by mechanical actuation. The triple-mode modulation allows heating/cooling for objects with all emissivity, thereby increase the versatility of radiativ ... Cite

Neural-adjoint method for the inverse design of all-dielectric metasurfaces.

Journal Article Optics express · March 2021 All-dielectric metasurfaces exhibit exotic electromagnetic responses, similar to those obtained with metal-based metamaterials. Research in all-dielectric metasurfaces currently uses relatively simple unit-cell designs, but increased geometrical complexity ... Full text Cite

Infrared all-dielectric Kerker metasurfaces.

Journal Article Optics express · March 2021 The unidirectional scattering of electromagnetic waves in the backward and forward direction, termed Kerkers' first and second conditions, respectively, is a prominent feature of sub-wavelength particles, which also has been found recently in all-dielectri ... Full text Cite

A triple-mode mid-infrared modulator for all-surface radiative thermal management

Conference Optics InfoBase Conference Papers · January 1, 2021 We demonstrate a mid-infrared modulator that can switch among reflectance, emittance, and transmittance by mechanical actuation. The triple-mode modulation allows heating/cooling for objects with all emissivity, thereby increase the versatility of radiativ ... Cite

Strain mapping with THz metamaterial composites

Conference Optics InfoBase Conference Papers · January 1, 2021 Terahertz metamaterials that exhibit broad spectral resonances are used to probe local strain fields. By choosing specific frequencies and polarizations for measurement, it is possible to obtain unique spatial maps for different strain states. ... Cite

Strain Mapping with THz Metamaterial Composites

Conference International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · November 8, 2020 Terahertz metamaterials with strain-sensitive junctions are introduced to identify structurally compromised regions of composite materials. Spatially mapping the local polarimetric metamaterial response visualizes and records regions of stress extrema expe ... Full text Cite

Machine Learning for Exotic Metasurfaces

Conference International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · November 8, 2020 We introduce one deep neural network and an inverse method called neural adjoint method to solve high-dimensional metasurface inverse design problem. We find that, even when the solution is outside the geometry space, the neural adjoint method is still abl ... Full text Cite

Correction to: Ultrathin Metasurface Wavelength-Selective Mirror for Millimeter/TerahertzWave Fabry-Perot Cavities (Journal of Infrared, Millimeter, and Terahertz Waves, (2020), 41, 4, (365-374), 10.1007/s10762-019-00657-2)

Journal Article Journal of Infrared, Millimeter, and Terahertz Waves · May 1, 2020 The original article contains error in one of the author family names John Koulakisf should read as John Koulakis. ... Full text Cite

Ultrathin Metasurface Wavelength-Selective Mirror for Millimeter/Terahertz Wave Fabry-Perot Cavities

Journal Article Journal of Infrared, Millimeter, and Terahertz Waves · April 1, 2020 We present an ultrathin metasurface working as both a highly reflective wavelength-selective mirror and a high transmittance output coupler for a semiconfocal Fabry-Perot cavity. The numerically optimized 2-μ m-thick metasurface achieves a peak reflectivit ... Full text Cite

Liquid crystal programmable metasurface for terahertz beam steering

Journal Article Applied Physics Letters · March 30, 2020 The coding metasurface integrated with tunable materials offers an attractive alternative to manipulate the THz beam dynamically. In this work, we demonstrate a THz programmable metasurface based on liquid crystal. The phase profile on the metasurface coul ... Full text Cite

Surface-wave-assisted nonreciprocity in spatio-temporally modulated metasurfaces.

Journal Article Nature communications · March 2020 Emerging photonic functionalities are mostly governed by the fundamental principle of Lorentz reciprocity. Lifting the constraints imposed by this principle could circumvent deleterious effects that limit the performance of photonic systems. Most efforts t ... Full text Cite

Benchmarking deep inverse models over time, and the neural-adjoint method

Conference Advances in Neural Information Processing Systems · January 1, 2020 We consider the task of solving generic inverse problems, where one wishes to determine the hidden parameters of a natural system that will give rise to a particular set of measurements. Recently many new approaches based upon deep learning have arisen, ge ... Cite

Strain sensing with THz metamaterial composites

Conference Optics InfoBase Conference Papers · January 1, 2020 Terahertz metamaterials with strain-sensitive junctions are introduced to identify structurally compromised regions of composite materials. Spatially mapping the local polarimetric metamaterial response visualizes and records regions of stress extrema expe ... Cite

Deep learning for accelerated all-dielectric metasurface design.

Journal Article Optics express · September 2019 Deep learning has risen to the forefront of many fields in recent years, overcoming challenges previously considered intractable with conventional means. Materials discovery and optimization is one such field, but significant challenges remain, including t ... Full text Cite

Multiple Epsilon-Near-Zero Resonances in Multilayered Cadmium Oxide: Designing Metamaterial-Like Optical Properties in Monolithic Materials

Journal Article ACS Photonics · May 15, 2019 In this Letter, we demonstrate a new class of infrared nanophotonic materials based on monolithic, multilayered doped cadmium oxide (CdO) thin films, where each CdO layer is individually tuned to support a separate epsilon-near-zero (ENZ) resonance. Infrar ... Full text Cite

Strain Sensing with Metamaterial Composites

Journal Article Advanced 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 ... Full text Cite

A Zero-Rank, Maximum Nullity Perfect Electromagnetic Wave Absorber

Journal Article Advanced Optical Materials · April 18, 2019 Electromagnetic wave absorbers formed from a metamaterial layer are demonstrated and near-perfect absorption is realized across much of the spectrum. Alternatively, an unpatterned low-loss dielectric layer forms an absorber of coherent light and shows near ... Full text Cite

Dynamic bound states in the continuum

Journal Article Optica · February 20, 2019 All-dielectric metasurfaces are a versatile platform to investigate a host of unconventional physical scattering responses. Effects, including high absorption and Huygens’ surfaces, have been demonstrated; however, a more exotic materialization-termed boun ... Full text Cite

Ultrathin tunable terahertz absorbers based on electrostatically actuated metamaterial

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2019 High performance tunable absorbers for terahertz (THz) frequencies will be crucial in advancing applications such as single-pixel imaging and spectroscopy. Metamaterials provide many new possibilities for manipulating electromagnetic waves at the subwavele ... Full text Cite

All-dielectric metasurfaces for terahertz science and technology

Conference International Conference on Metamaterials, Photonic Crystals and Plasmonics · January 1, 2019 All-dielectric metasurfaces are useful for investigation of new devices for terahertz science and technology. Scattering effects ranging from high absorption and Huygens' reflect arrays to bound-states-in-the-continuum (BIC) suggest their use for applicati ... Cite

Role of loss in all-dielectric metasurfaces.

Journal Article Optics express · June 2018 Arrays of dielectric cylinders support two fundamental dipole active eigenmodes, which can be manipulated to elicit a variety of electromagnetic responses in all-dielectric metamaterials. Dissipation is a critical parameter in determining functionality; th ... Full text Cite

Phototunable Dielectric Huygens' Metasurfaces.

Journal Article Advanced materials (Deerfield Beach, Fla.) · May 2018 Conventional dielectric metasurfaces achieve their properties through geometrical tuning and consequently are static. Although some unique properties are demonstrated, the usefulness for realistic applications is thus inherently limited. Here, control of t ... Full text Cite

Resonance-domain diffractive lens for the terahertz region.

Journal Article Optics letters · May 2018 Diffractive optics has long served as the basis of spectroscopic measurements of materials. Operation in the resonance domain further allows these elements to achieve high efficiency and polarization control. An effective grating theory is a practical tool ... Full text Cite

Temporal coupled mode theory for all-dielectric perfect absorbers

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2018 Mechanism of the two-port one input mirror-symmetric all-dielectric disk array perfect absorbers is studied by temporal coupled mode theory. The perfect absorption is resulted from the degenerate critical coupling of EH111 and HE111 modes of the dielectric ... Full text Cite

All-dielectric metasurfaces for THz imaging and sensing

Conference Optics InfoBase Conference Papers · January 1, 2018 We demonstrate an approach to terahertz imaging and sensing using all-dielectric metasurface absorbers. THz waves are absorbed by the metasurface, converted to heat, and detected by an infrared camera. ... Full text Cite

Fast tunable terahertz absorber based on a MEMS-driven metamaterial

Conference 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings · October 25, 2017 We present an experimental study of ultra-Thin tunable THz absorbers based on MEMSdriven metamaterials. Using the high mechanical sensitivity of thin subwavelength metamaterial absorbers, we proposed a paradigm to combine meta-Atoms and suspended flat memb ... Full text Cite

Degenerate critical coupling in all-dielectric metasurface absorbers.

Journal Article Optics express · October 2017 We develop the theory of all-dielectric absorbers based on temporal coupled mode theory (TCMT), with parameters extracted from eigenfrequency simulations. An infinite square array of cylindrical resonators embedded in air is investigated, and we find that ... Full text Cite

Multiplexed coded time domain sampling with metamaterials.

Journal Article Optics express · October 2017 The far infrared region of the electromagnetic spectrum often necessitates the use of thermal detectors that, by nature, typically have poor response times and diminished sensitivities, at least compared to adjacent bands. However, many signals of interest ... Full text Cite

Graphene metamaterial spatial light modulator for infrared single pixel imaging.

Journal Article Optics express · October 2017 High-resolution and hyperspectral imaging has long been a goal for multi-dimensional data fusion sensing applications - of interest for autonomous vehicles and environmental monitoring. In the long wave infrared regime this quest has been impeded by size, ... Full text Cite

Ultra-thin infrared metamaterial detector for multicolor imaging applications.

Journal Article Optics express · September 2017 The next generation of infrared imaging systems requires control of fundamental electromagnetic processes - absorption, polarization, spectral bandwidth - at the pixel level to acquire desirable information about the environment with low system latency. Me ... Full text Cite

Properties of dynamical electromagnetic metamaterials

Journal Article Journal of Optics (United Kingdom) · August 1, 2017 Electromagnetic metamaterials consist of two or three dimensional arrays of tailored metallic and/or dielectric inclusions and provide unprecedented sub-wavelength control over light-matter interactions. Metamaterials are fashioned to yield a specific resp ... Full text Cite

Strong Broadband Terahertz Optical Activity through Control of the Blaschke Phase with Chiral Metasurfaces

Journal Article Physical Review Applied · July 21, 2017 We demonstrate terahertz chiral metamaterials that achieve resonant transmission and strong optical activity. This response is realized in a metasurface coupled to its Babinet complement, with additional twist. Uniquely, the optical activity achieved in th ... Full text Cite

All-dielectric metasurface absorbers for uncooled terahertz imaging

Journal Article Optica · June 20, 2017 Imaging in the terahertz (THz) range of the electromagnetic spectrum is difficult owing to the lack of high-power sources and efficient detectors. For decades, there has been tremendous effort to fashion focal plane arrays for THz imaging owing to the grea ... Full text Cite

Reconfigurable room temperature metamaterial infrared emitter

Journal Article Optica · April 20, 2017 The marriage of micro/nanoelectromechanical systems with metamaterials offers a viable route to achieving reconfigurable devices, which control the emission of energy. Here we propose and demonstrate the idea of a metamaterial microelectromechanical system ... Full text Cite

Multifunctional metamaterial pyroelectric infrared detectors

Journal Article Optica · February 20, 2017 Pyroelectric materials enable the construction of highperformance yet low-cost and uncooled detectors throughout the infrared spectrum. These devices have been used as broadband sensors and, when combined with an interferometric element or filter, can prov ... Full text Cite

Experimental realization of a terahertz all-dielectric metasurface absorber.

Journal Article Optics express · January 2017 Metamaterial absorbers consisting of metal, metal-dielectric, or dielectric materials have been realized across much of the electromagnetic spectrum and have demonstrated novel properties and applications. However, most absorbers utilize metals and thus ar ... Full text Cite

Fast tunable terahertz absorber based on a MEMS-driven metamaterial

Conference Optics InfoBase Conference Papers · January 1, 2017 We present an experimental study of ultra-thin tunable THz absorbers based on MEMSdriven metamaterials. Using the high mechanical sensitivity of thin subwavelength metamaterial absorbers, we proposed a paradigm to combine meta-atoms and suspended flat memb ... Full text Cite

Frequency division multiplexing THz light field imaging

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2017 We present a single pixel frequency division multiplexing imaging system with two metamaterial spatial light modulators (SLMs) for THz light field imaging. One SLM is used for slicing/modulating the 4D light field from various sub-apertures, while the seco ... Full text Cite

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial.

Journal Article Microsystems & nanoengineering · January 2017 The realization of high-performance tunable absorbers for terahertz frequencies is crucial for advancing applications such as single-pixel imaging and spectroscopy. Based on the strong position sensitivity of metamaterials' electromagnetic response, we com ... Full text Cite

Mimicking liquid crystals with metamaterials

Conference 2016 Conference on Lasers and Electro-Optics, CLEO 2016 · December 16, 2016 We propose and demonstrate Meta Liquid Crystals (MLCs), a novel form of tunable 3D metamaterials. MLCs mimic the response of liquid crystals but use meta-atoms instead of molecular mesogens, enabling richer variety of electromagnetic responses. ... Full text Cite

Design and fabrication of a multispectral infrared metamaterial detector

Conference 2016 Conference on Lasers and Electro-Optics, CLEO 2016 · December 16, 2016 Infrared imaging systems require new technologies at the pixel level to provide enhanced spectral sensitivity with similar function to cones and rods in the human retina. A multicolor imaging system can be accomplished with the aid of metamaterials to spec ... Full text Cite

Graphene metamaterial modulator for free-space thermal radiation.

Journal Article Optics express · October 2016 We proposed and demonstrated a new metamaterial architecture capable of high speed modulation of free-space space thermal infrared radiation using graphene. Our design completely eliminates channel resistance, thereby maximizing the electrostatic modulatio ... Full text Cite

Superiority of terahertz over infrared transmission through bandages and burn wound ointments

Journal Article Applied Physics Letters · June 6, 2016 Terahertz electromagnetic waves have long been proposed to be ideal for spectroscopy and imaging through non-polar dielectric materials that contain no water. Terahertz radiation may thus be useful for monitoring burn and wound injury recovery, as common c ... Full text Cite

Light-Matter interactions

Chapter · April 19, 2016 Cite

Role of surface electromagnetic waves in metamaterial absorbers.

Journal Article Optics express · March 2016 Metamaterial absorbers have been demonstrated across much of the electromagnetic spectrum and exhibit both broad and narrow-band absorption for normally incident radiation. Absorption diminishes for increasing angles of incidence and transverse electric po ... Full text Cite

Frequency-division-multiplexed single-pixel imaging with metamaterials

Journal Article Optica · February 20, 2016 We propose and experimentally realize the concept of frequency-division-multiplexed single-pixel imaging. Our technique relies entirely on meta material spatial light modulators, the advent of which has permitted advanced modulation techniques difficult to ... Full text Cite

Tunable Meta-Liquid Crystals.

Journal Article Advanced materials (Deerfield Beach, Fla.) · February 2016 Meta-liquid crystals, a novel form of tunable 3D metamaterials, are proposed and experimentally demonstrated in the terahertz frequency regime. A morphology change under a bias electric field and a strong modulation of the transmission are observed. In com ... Full text Open Access Cite

Thermochromic Infrared Metamaterials.

Journal Article Advanced materials (Deerfield Beach, Fla.) · February 2016 An infrared artificial thermochromic material composed of a metamaterial emitter and a bimaterial micro-electro-mechanical system is investigated. A differential emissivity of over 30% is achieved between 623 K and room temperature. The passive metamateria ... Full text Open Access Cite

Single Pixel Quadrature Imaging with Metamaterials

Journal Article Advanced Optical Materials · January 1, 2016 Quadrature amplitude modulation is implemented in a single pixel imaging system, enabled by all-electronic metamaterial spatial light modulation. Experimental images at 3.2 THz are acquired to demonstrate the expected doubling of efficiency over previous s ... Full text Cite

Electronic and thermally tunable infrared metamaterial absorbers

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 In this paper, we report a computational and experimental study using tunable infrared (IR) metamaterial absorbers (MMAs) to demonstrate frequency tunable (7%) and amplitude modulation (61%) designs. The dynamic tuning of each structure was achieved throug ... Full text Cite

Design and Fabrication of a Multispectral Infrared Metamaterial Detector

Conference Optics InfoBase Conference Papers · January 1, 2016 Infrared imaging systems require new technologies at the pixel level to provide enhanced spectral sensitivity with similar function to cones and rods in the human retina. A multicolor imaging system can be accomplished with the aid of metamaterials to spec ... Cite

Mimicking Liquid Crystals with Metamaterials

Conference Optics InfoBase Conference Papers · January 1, 2016 We propose and demonstrate Meta Liquid Crystals (MLCs), a novel form of tunable 3D metamaterials. MLCs mimic the response of liquid crystals but use meta-atoms instead of molecular mesogens, enabling richer variety of electromagnetic responses. ... Cite

Flexible thin-film black gold membranes with ultrabroadband plasmonic nanofocusing for efficient solar vapour generation.

Journal Article Nature communications · December 2015 Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-to-heat conversion from a wider solar spectrum, we employ adiabatic plasmo ... Full text Cite

Quadrature & frequency diverse terahertz imaging with metamaterials

Conference IRMMW-THz 2015 - 40th International Conference on Infrared, Millimeter, and Terahertz Waves · November 11, 2015 Compressive sensing is an exciting approach to imaging and promises to make significant advance in the terahertz regime. However, compressive imaging is commonly implemented is such that acquisition proceeds in a serial manner, thus leading to unrealistic ... Full text Cite

Digital metamaterials for single pixel imaging in the Far Infrared

Conference 2015 1st URSI Atlantic Radio Science Conference, URSI AT-RASC 2015 · October 21, 2015 Single pixel cameras are useful imaging devices where it is difficult or infeasible to fashion focal plan arrays. For example in the Far Infrared (FIR) - and longer wavelength ranges - it is difficult to perform imaging by conventional detector arrays, owi ... Full text Cite

Metamaterial-based single pixel imaging system (Presentation Recording)

Conference Metamaterials, Metadevices, and Metasystems 2015 · October 5, 2015 Full text Cite

Taming blackbody radiation with MEMS metamaterials

Conference International Conference on Optical MEMS and Nanophotonics · October 2, 2015 MEMS based metamaterials are an ideal architecture to provide dynamic electromagnetic properties in the infrared range of the electromagnetic spectrum. We detail several realizations of infrared MEMS metamaterials and discuss potential applications. ... Full text Cite

Artificial electrochromic & thermochromic infrared metamaterials

Conference International Conference on Optical MEMS and Nanophotonics · October 2, 2015 Controlling the emission of surface energy lies at the heart of many energy harvesting applications. However, the emission is strongly tied to the temperature of the object and there is little ability for modification. In this paper, we describe the design ... Full text Cite

Broadband and ultrahigh optical haze thin films with self-aggregated alumina nanowire bundles for photovoltaic applications

Journal Article Energy and Environmental Science · September 1, 2015 Featured Publication Optical haze is one of the most important factors to be considered in the development of efficient photonic and optoelectronic devices by manipulating the light behavior. In this work, we fabricated a high optical haze film composed of self-aggregated alum ... Full text Cite

Bi-layer metamaterials as fully functional near-perfect infrared absorbers

Journal Article Applied Physics Letters · July 13, 2015 Featured Publication In this letter, we discuss the design, fabrication, and experimental characterization of a bi-layer fully functional near-perfect metamaterial absorber (MMA) in the long-wavelength infrared (LWIR), which is broadband and generally insensitive to polarizati ... Full text Open Access Cite

Mechanically tunable bi-layer terahertz metamaterials

Journal Article CLEO: Science and Innovations, CLEO-SI 2015 · May 4, 2015 We propose a post-processing approach for tuning terahertz metamaterials by modifying the coupling between two metamaterial layers. We demonstrate that this method allows the metamaterial resonance to be shifted by 31% of the central frequency. © OSA 2015. ... Full text Cite

Dynamic electromagnetic metamaterials

Journal Article Materials Today · January 1, 2015 Featured Publication Electromagnetic metamaterials are designer materials made from 'artificial atoms' which provide unprecedented control over light matter interactions. Metamaterials are fashioned to yield a specific response to the electric and magnetic components of light ... Full text Cite

Post-processing approach for tuning multi-layered metamaterials

Journal Article Applied Physics Letters · October 13, 2014 Featured Publication We propose a post-processing approach to efficiently tune the resonance frequency in double-layered terahertz metamaterials separated by a bonding agent. By heating the bonding agent, it is possible to move one metamaterial layer laterally with respect to ... Full text Cite

Plasmonic Resonance toward Terahertz Perfect Absorbers

Journal Article ACS Photonics · July 16, 2014 Featured Publication Metamaterial perfect absorbers have garnered significant interest with applications in sensing, imaging, and energy harnessing. Of particular interest are terahertz absorbers to overcome the weak terahertz response of natural materials. Here, we propose lo ... Full text Cite

Stable high temperature metamaterial emitters for thermophotovoltaic applications

Journal Article Applied Physics Letters · May 19, 2014 Featured Publication We report a metamaterial design for a thermophotovoltaic (TPV) emitter. TPVs are similar to photovoltaic solar cells, but they convert heat to electricity instead of sunlight. The focus of this paper is on the emitter stage of the TPV system, which convert ... Full text Cite

Liquid crystal metamaterial absorber spatial light modulator for THz applications

Journal Article Advanced Optical Materials · March 1, 2014 Featured Publication A terahertz (THz) spatial light modulator implemented with metamaterial absorbers (MMAs) functionalized with isothiocyanate-based liquid crystals (LCs) is experimentally demonstrated. The device is designed to work in reflection mode and is arranged in a 6 ... Full text Cite

Coded and compressive THz imaging with metamaterials

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2014 Featured Publication 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 involve me ... Full text Cite

Terahertz compressive imaging with metamaterial spatial light modulators

Journal Article Nature Photonics · 2014 Featured Publication Cite

Terahertz compressive imaging with metamaterial spatial light modulators

Journal Article Nature Photonics · January 1, 2014 Featured Publication 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 ... Full text Cite

Sparse imaging with metamaterials at terahertz frequencies

Journal Article Conference on Lasers and Electro-Optics Europe - Technical Digest · January 1, 2014 Metamaterials are composite structures which permit unprecedented control over light matter interactions. Here we show use of metamaterials as spatial light modulators permitting single pixel compressive imaging at terahertz frequencies. ... Cite

Sparse imaging with metamaterials at terahertz frequencies

Journal Article Optics InfoBase Conference Papers · January 1, 2014 Metamaterials are composite structures which permit unprecedented control over light matter interactions. Here we show use of metamaterials as spatial light modulators permitting single pixel compressive imaging at terahertz frequencies. © 2014 OSA. ... Cite

Terahertz properties of metallic checkerboard patterns and related structures

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2014 A critical electromagnetic response of a self-complementary structure was investigated. The nearly perfect selfcomplementary checkerboard patterns were fabricated by the electron-beam lithography and their electromagnetic responses are measured in the tera ... Full text Cite

Sparse imaging with metamaterials at terahertz frequencies

Conference Optics InfoBase Conference Papers · January 1, 2014 Metamaterials are composite structures which permit unprecedented control over light matter interactions. Here we show use of metamaterials as spatial light modulators permitting single pixel compressive imaging at terahertz frequencies. © 2014 OSA. ... Full text Cite

Interferometric direction finding with a metamaterial detector

Journal Article Applied Physics Letters · December 16, 2013 Featured Publication We present measurements and analysis demonstrating useful direction finding of sources in the S band (2-4 GHz) using a metamaterial detector. An augmented metamaterial absorber that supports magnitude and phase measurement of the incident electric field, w ... Full text Cite

Four-color metamaterial absorber THz spatial light modulator

Journal Article Advanced Optical Materials · December 1, 2013 Featured Publication Full text Cite

THz imaging with metamaterials

Conference International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · December 1, 2013 Metamaterials have demonstrated the ability to efficiently alter electromagnetic radiation in the terahertz range. The use of semiconductors as substrates, or as part of the metamaterial itself, has enabled real-time dynamic control providing spatial and f ... Full text Cite

Introduction to the special issue

Journal Article IEEE Transactions on Terahertz Science and Technology · November 1, 2013 The articles in this special issue focus on metamaterials and their applications. © 2011-2012 IEEE. ... Full text Cite

Spin-induced optical conductivity in the spin-liquid candidate herbertsmithite.

Journal Article Physical review letters · September 2013 Featured Publication We report a direct measurement of the low-frequency optical conductivity of large-area single-crystal herbertsmithite, a promising spin-liquid candidate material, by means of terahertz time-domain spectroscopy. In the spectral range below 1.4 THz, we obser ... Full text Cite

Dynamic Manipulation of Infrared Radiation with MEMS Metamaterials

Journal Article Advanced Optical Materials · August 1, 2013 Featured Publication An electrically tunable MEMS metamaterial that effectively manipulates radiation in the mid-infrared wavelength range is experimentally demonstrated. The metamaterial consists of an array of suspended metal-dielectric elements above a metal ground plane on ... Full text Cite

Metamaterial-based imaging for potential security applications

Conference Proceedings of SPIE - The International Society for Optical Engineering · June 3, 2013 Featured Publication In this paper, we present two different types of THz spatial light modulators (SLMs) that use dynamic metamaterials (MMs) to enable multiplex imaging. One imaging setup consists of a doped semiconducting MM as the SLM, with multi-color super-pixels compose ... Full text Cite

Terahertz single pixel imaging with an optically controlled dynamic spatial light modulator.

Journal Article Optics express · May 2013 Featured Publication We present a single pixel terahertz (THz) imaging technique using optical photoexcitation of semiconductors to dynamically and spatially control the electromagnetic properties of a semiconductor mask to collectively form a THz spatial light modulator (SLM) ... Full text Cite

Broadband light-trapping enhancement in an ultrathin film a-Si absorber using whispering gallery modes and guided wave modes with dielectric surface-textured structures.

Journal Article Advanced materials (Deerfield Beach, Fla.) · May 2013 Featured Publication An embedded nanosphere dielectric structure on an a-Si ultrathin film improves weighted absorption from 23.8% to 39.9%. The PMMA embedding layer offers a guided wave mode as well as mechanical robustness, in addition to the resonant whispering gallery mode ... Full text Cite

Liquid crystal tunable metamaterial absorber.

Journal Article Physical review letters · April 2013 Featured Publication We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the metamaterial unit cell, we are able to modify the absorption by ... Full text Cite

A Subwavelength Extraordinary-Optical-Transmission Channel in Babinet Metamaterials

Journal Article Advanced Optical Materials · March 1, 2013 Featured Publication Babinet metamaterials exhibit higher transmission efficiencies at lower frequencies than traditional extraordinary-optical-transmission designs and provide an additional parameter for the creation of more efficient aperture structures, which may be useful ... Full text Cite

Optical Transmission: A Subwavelength Extraordinary-Optical-Transmission Channel in Babinet Metamaterials (Advanced Optical Materials 3/2013)

Journal Article Advanced Optical Materials · March 1, 2013 Featured Publication W. J. Padilla and co-workers report on page 221 extremely subwavelength extraordinary optical transmission (EOT) using Babinet metamaterial apertures. The front cover image depicts enhanced transmission and the importance of the strong coupling between lig ... Full text Cite

THz wave modulators: A brief review on different modulation techniques

Journal Article Journal of Infrared, Millimeter, and Terahertz Waves · January 1, 2013 We review different techniques for modulation of the electromagnetic properties of terahertz (THz) waves. We discuss various approaches for electronic, optical, thermal and nonlinear modulation in distinct material systems such as semiconductors, graphene, ... Full text Cite

Taming the blackbody with metamaterials for energy harvesting applications

Journal Article Laser Science, LS 2012 · December 1, 2012 The metamaterial perfect absorber has been shown across the electromagnetic spectrum. These engineered, near unity, absorbers yield performance flexibility and here we demonstrate their use for energy harvesting devices-in particular for thermophotovoltaic ... Cite

Experimental realization of a metamaterial detector focal plane array.

Journal Article Physical review letters · October 2012 We present a metamaterial absorber detector array that enables room-temperature, narrow-band detection of gigahertz (GHz) radiation in the S band (2-4 GHz). The system is implemented in a commercial printed circuit board process and we characterize the det ... Full text Cite

Loss compensation in metamaterials through embedding of active transistor based negative differential resistance circuits.

Journal Article Optics express · September 2012 Dielectric and ohmic losses in metamaterials are known to limit their practical use. In this paper, an all-electronic approach for loss compensation in metamaterials is presented. Each unit cell of the meta-material is embedded with a cross-coupled transis ... Full text Cite

Metamaterial electromagnetic wave absorbers.

Journal Article Advanced materials (Deerfield Beach, Fla.) · June 2012 The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-t ... Full text Cite

Extremely subwavelength planar magnetic metamaterials

Journal Article Physical Review B - Condensed Matter and Materials Physics · May 16, 2012 We present highly subwavelength magnetic metamaterials designed for operation at radio frequencies (rf's). A dual-layer design consisting of independent planar spiral elements enables the experimental demonstration of a unit cell size (a) that is ∼700 time ... Full text Cite

Magnetic levitation of metamaterial bodies enhanced with magnetostatic surface resonances

Journal Article Physical 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 ... Full text Open Access Cite

Single-layer terahertz metamaterials with bulk optical constants

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 17, 2012 We investigate the conditions under which single layer metamaterials may be described by bulk optical constants. Terahertz time domain spectroscopy is utilized to investigate two types of geometries, both with two different sizes of embedding dielectric-cu ... Full text Cite

Mems and metamaterial-based terahertz detector

Journal Article Technical Digest - Solid-State Sensors, Actuators, and Microsystems Workshop · January 1, 2012 We have designed, fabricated and characterized metamaterials-based far-infrared detector. The detector design, which combines metamaterials (MMs) and MEMS, is frequency selective. The enhanced absorption on the cantilever pixels from split-ring resonators ... Full text Cite

Taming the blackbody with metamaterials for energy harvesting applications

Conference Laser Science, LS 2012 · January 1, 2012 The metamaterial perfect absorber has been shown across the electromagnetic spectrum. These engineered, near unity, absorbers yield performance flexibility and here we demonstrate their use for energy harvesting devices-in particular for thermophotovoltaic ... Full text Cite

Broadband optical antireflection enhancement by integrating antireflective nanoislands with silicon nanoconical-frustum arrays.

Journal Article Advanced materials (Deerfield Beach, Fla.) · December 2011 Based on conventional colloidal nanosphere lithography, we experimentally demonstrate novel graded-index nanostructures for broadband optical antireflection enhancement including the near-ultraviolet (NUV) region by integrating residual polystyrene antiref ... Full text Cite

Metamaterial based terahertz detector

Journal Article Optics InfoBase Conference Papers · December 1, 2011 We present a metamaterial based terahertz (THz) detector. The detector design, which combines metamaterials and MEMs, is frequency selective, and we have fabricated and tested detectors at 95 GHz and 693 GHz with noise equivalent powers of 1.13 x 10-8 W/√H ... Cite

Metamaterial based terahertz detector

Journal Article IRMMW-THz 2011 - 36th International Conference on Infrared, Millimeter, and Terahertz Waves · December 1, 2011 We have designed, fabricated, and characterized metamaterial enhanced bimaterial cantilever pixels for thermally based far-infrared detection. Local heating due to absorption from split ring resonators incorporated directly onto the cantilever pixels leads ... Full text Cite

Controlling Gigahertz and Terahertz Surface ElectromagneticWaves with Metamaterial Resonators

Journal Article Physical 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 ... Full text Cite

Microwave and terahertz wave sensing with metamaterials.

Journal Article Optics express · October 2011 We have designed, fabricated, and characterized metamaterial enhanced bimaterial cantilever pixels for far-infrared detection. Local heating due to absorption from split ring resonators (SRRs) incorporated directly onto the cantilever pixels leads to mecha ... Full text Cite

Extreme subwavelength electric GHz metamaterials

Journal Article Journal of Applied Physics · September 1, 2011 We investigate electric GHz metamaterial resonator arrays with strong electric responses with the goal of reducing the resonator size in comparison to the excitation wavelength. By exploiting capactive coupling between adjacent resonators, we achieve a lar ... Full text Cite

Taming the blackbody with infrared metamaterials as selective thermal emitters.

Journal Article Physical review letters · July 2011 In this Letter we demonstrate, for the first time, selective thermal emitters based on metamaterial perfect absorbers. We experimentally realize a narrow band midinfrared (MIR) thermal emitter. Multiple metamaterial sublattices further permit construction ... Full text Cite

High speed terahertz modulation from metamaterials with embedded high electron mobility transistors.

Journal Article Optics express · May 2011 We present a computational and experimental study of a novel terahertz (THz) device resulting from hybridization of metamaterials with pseudomorphic high electron mobility transistors (HEMTs), fabricated in a commercial gallium arsenide (GaAs) process. Mon ... Full text Cite

MEMS based structurally tunable metamaterials at terahertz frequencies

Journal Article Journal of Infrared, Millimeter, and Terahertz Waves · May 1, 2011 We present the design, simulation, fabrication and characterization of structurally tunable metamaterials showing a marked tunability of the electric and magnetic responses at terahertz frequencies. Our results demonstrate that structurally tunable metamat ... Full text Cite

Recent progress in electromagnetic metamaterial devices for Terahertz applications

Journal Article IEEE Journal on Selected Topics in Quantum Electronics · January 1, 2011 Recent advances in metamaterials (MMs) research have highlighted the possibility to create novel devices with unique electromagnetic (EM) functionality. Indeed, the power of MMs lies in the fact that it is possible to construct materials with a user-design ... Full text Cite

Metamaterial based terahertz detector

Journal Article 2011 Conference on Lasers and Electro-Optics: Laser Science to Photonic Applications, CLEO 2011 · January 1, 2011 We present a metamaterial based terahertz (THz) detector. The detector design, which combines metamaterials and MEMs, is frequency selective, and we have fabricated and tested detectors at 95 GHz and 693 GHz with noise equivalent powers of 1.13 108 W/Hz an ... Full text Cite

Performance enhancement of terahertz metamaterials on ultrathin substrates for sensing applications

Journal Article Applied Physics Letters · December 27, 2010 We design, fabricate, and characterize split-ring resonator (SRR) based planar terahertz metamaterials (MMs) on ultrathin silicon nitride substrates for biosensing applications. Proof-of-principle demonstration of increased sensitivity in thin substrate SR ... Full text Cite

Embedded HEMT/metamaterial composite devices for active terahertz modulation

Journal Article 2010 23rd Annual Meeting of the IEEE Photonics Society, PHOTINICS 2010 · December 1, 2010 Full text Cite

Structurally reconfigurable metamaterials at terahertz frequencies

Journal Article Optics InfoBase Conference Papers · December 1, 2010 We demonstrate structurally reconfigurable metamaterials with a marked tunability of both electric and magnetic responses at terahertz frequencies where artificial "atoms" reorient within unit cells in response to an external stimulus. ... Cite

External modulators for TeraHertz Quantum Cascade Lasers based on electrically-driven active metamaterials

Journal Article Metamaterials · August 1, 2010 We have designed, fabricated and measured electrically-driven active metamaterials which operate as external modulators for TeraHertz Quantum Cascade Lasers. The modulation is achieved by applying a voltage to the metamaterial layer which actively displace ... Full text Cite

Percolation and polaritonic effects in periodic planar nanostructures evolving from holes to islands

Journal Article Applied Physics Letters · July 26, 2010 We study interaction of the electromagnetic radiation with a series of thin film periodic nanostructures evolving from holes to islands. We show, through model calculations, simulations, and experiments, that the responses of these structures evolve accord ... Full text Cite

High performance optical absorber based on a plasmonic metamaterial

Journal Article Applied Physics Letters · June 21, 2010 High absorption efficiency is particularly desirable at present for various microtechnological applications including microbolometers, photodectors, coherent thermal emitters, and solar cells. Here we report the design, characterization, and experimental d ... Full text Cite

A dual band terahertz metamaterial absorber

Journal Article Journal of Physics D: Applied Physics · June 3, 2010 We present the design, fabrication and characterization of a dual band metamaterial absorber which experimentally shows two distinct absorption peaks of 0.85 at 1.4 THz and 0.94 at 3.0 THz. The dual band absorber consists of a dual band electric-field-coup ... Full text Cite

Elimination of phase singularity to achieve superresolution in lossy metamaterials.

Journal Article Optics express · June 2010 The presence of absorption losses softens the singular behavior of transmission resonances and leads to a good image in spite of limited effective spatial frequency range. Nonetheless, we found that the phase singularity does not disappear despite the cons ... Full text Cite

Infrared spatial and frequency selective metamaterial with near-unity absorbance.

Journal Article Physical review letters · May 2010 We demonstrate, for the first time, a spatially dependent metamaterial perfect absorber operating in the infrared regime. We achieve an experimental absorption of 97% at a wavelength of 6.0   μm, and our results agree well with numerical full-wave simulati ... Full text Cite

THz plasmonic waves launchers for metamaterials studies

Journal Article 2010 IEEE Photonics Society Winter Topicals Meeting Series, WTM 2010 · April 28, 2010 Full text Cite

Towards a two-dimensional superconducting state of La(2-x)Sr(x)CuO4 in a moderate external magnetic field.

Journal Article Physical review letters · April 2010 We report a novel aspect of the competition and coexistence between magnetism and superconductivity in the high-T(c) cuprate La(2-x)Sr(x)CuO4 (La214). With a modest magnetic field applied H parallel c axis, we monitored the infrared signature of pair tunne ... Full text Cite

Possibility of magnetic-field-induced reconstruction of the Fermi surface in underdoped cuprates: Constraints from infrared magneto-optics

Journal Article Physical Review B - Condensed Matter and Materials Physics · February 19, 2010 We present an analysis of infrared optical and magneto-optical conductivity data for a range of underdoped cuprate superconductors including YBa2 Cu3 Oy and La2-x Srx CuO4. In light of recent magneto-oscillation experiments which have been interpreted in t ... Full text Cite

Metamaterials on parylene thin film substrates: Design, fabrication, and characterization at terahertz frequency

Journal Article Applied Physics Letters · February 8, 2010 We design, fabricate, and characterize terahertz (THz) resonant metamaterials on parylene free-standing thin film substrates. Several different metamaterials are investigated and our results show strong electromagnetic responses at THz frequencies ranging ... Full text Cite

Structurally reconfigurable metamaterials at terahertz frequencies

Journal Article Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010 · January 1, 2010 We demonstrate structurally reconfigurable metamaterials with a marked tunability of both electric and magnetic responses at terahertz frequencies where artificial "atoms" reorient within unit cells in response to an external stimulus. ©2010 IEEE. ... Full text Cite

Blackbody engineering with metamaterials

Conference 34th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2009 · December 31, 2009 We demonstrate metamaterial absorbers which control the emissivity spectrum of a body at a particular temperature over a bandwidth of 50%, and may be applied as coatings to materials to control their blackbody emission spectra. © 2009 IEEE. ... Full text Cite

Metamaterial devices for the terahertz gap

Conference APMC 2009 - Asia Pacific Microwave Conference 2009 · December 1, 2009 Metamaterials are engineered materials which offer superb electromagnetic performance over naturally occurring materials, and offer great potential to construct novel devices operating in the terahertz frequency regime. Here we experimentally demonstrate m ... Full text Cite

A broadband terahertz metamaterial electrical modulator

Conference Optics InfoBase Conference Papers · December 1, 2009 We demonstrate hybrid metamaterial devices that are able to electrically switch their resonances therefore the terahertz transmission properties at room temperature. The interrelated amplitude switching and phase shifting allow for fast broadband external ... Cite

Flexible terahertz metamaterials on polyimide substrates

Journal Article Optics InfoBase Conference Papers · December 1, 2009 Flexible resonant terahertz metamaterials built on ultrathin highly flexible polyimide substrates have been designed, fabricated and measured. Our results provide a path forward for creating multi-layer non-planar metamaterials at terahertz frequencies. © ... Cite

Flexible wide angle terahertz resonant absorber based on perfectly impedance matched metamaterials

Journal Article Optics InfoBase Conference Papers · December 1, 2009 We present the design, fabrication and characterization of a highly flexible metamaterial absorber that experimentally obtains an absorptivity of 0.96 at 1.6 THz and operates over wide angular range for transverse electric and transverse magnetic radiation ... Cite

Plasmonic waveguides and metamaterial components at terahertz frequencies

Journal Article APMC 2009 - Asia Pacific Microwave Conference 2009 · December 1, 2009 The electromagnetic field around a planar plasmonic waveguide can be used for the study of single metamaterial components such as single or double split ring resonators (SRR). The resonances in the terahertz (THz) frequency range of these devices will be s ... Full text Cite

Flexible and reconfigurable terahertz metamaterials

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · November 18, 2009 Metamaterial and plasmonic composites have led to the realization that new possibilities abound for creating materials displaying functional electromagnetic properties not realized by nature. Recently, we have extended these ideas by combining metamaterial ... Full text Cite

Flexible terahertz metamaterials on polyimide substrates

Journal Article 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 18, 2009 Flexible resonant terahertz metamaterials built on ultrathin highly flexible polyimide substrates have been designed, fabricated and measured. Our results provide a path forward for creating multi-layer non-planar metamaterials at terahertz frequencies. ©2 ... Cite

External modulation of terahertz quantum cascade lasers using electrically-driven active metamaterials

Journal Article 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · November 16, 2009 We have designed, fabricated and measured a first generation external modulator for a ∼2.4 terahertz Quantum Cascade Laser based on an electrically-driven active terahertz metamaterial structure. ©2008 Optical Society of America. ... Cite

Reconfigurable terahertz metamaterials.

Journal Article Physical review letters · October 2009 We demonstrate reconfigurable anisotropic metamaterials at terahertz frequencies where artificial "atoms" reorient within unit cells in response to an external stimulus. This is accomplished by fabricating planar arrays of split ring resonators on bimateri ... Full text Cite

Guiding light with conformal transformations.

Journal Article Optics express · August 2009 The past decade has seen a revolution in electromagnetics due to the development of metamaterials. These artificial composites have been fashioned to exhibit exotic effects such as a negative index of refraction. However, the full potential of metamaterial ... Full text Cite

Terahertz metamaterials

Conference Proceedings of SPIE - The International Society for Optical Engineering · June 16, 2009 In this paper we present our recent developments in terahertz (THz) metamaterials and devices. Planar THz metamaterials and their complementary structures fabricated on suitable substrates have shown electric resonant response, which causes the band-pass o ... Full text Cite

Thrahertz metamaterials with simultaneously negative electric and magnetic resonance based on bimaterial pop up structures

Journal Article Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) · June 1, 2009 In this paper, we present a metamaterial with simultaneously negative electric and magnetic resonance responses in the terahertz (THz) frequency range. The structure is composed of in-plane split resonator rings (SRRs) for desired electric response and out ... Full text Cite

Large-area metamaterials on thin membranes for multilayer and curved applications at terahertz and higher frequencies

Journal Article Applied Physics Letters · May 6, 2009 A possible path for fabricating three-dimensional metamaterials with curved geometries at optical and infrared frequencies is to stack flexible metamaterial layers. We have fabricated highly uniform metamaterials at terahertz frequencies on large-area, low ... Full text Cite

Magnetic field induced modification of superfluid density and interplane spectral weight in YBa2 Cu3 Oy

Journal Article Physical Review B - Condensed Matter and Materials Physics · March 3, 2009 We report on the interlayer infrared response of YBa2 Cu3 Oy in an applied magnetic field. This study explores both the underdoped (y=6.67 and 6.75) and optimally doped (y=6.95) regions of the phase diagram, and includes data for fields applied both parall ... Full text Cite

Design, theory, and measurement of a polarization-insensitive absorber for terahertz imaging

Journal Article Physical 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 ... Full text Cite

A metamaterial solid-state terahertz phase modulator

Journal Article Nature Photonics · March 1, 2009 Over the past two decades, terahertz time-domain spectroscopy and quantum-cascade lasers have been two of the most important developments in terahertz science and technology. These technologies may contribute to a multitude of terahertz applications that a ... Full text Cite

Dynamic Metamaterials at Terahertz Frequencies

Conference · January 1, 2009 Metamaterials fabricated for operation at terahertz frequencies are presented. Optical excitation enables control of the metamaterial resonance amplitude and frequency. ... Full text Cite

A broadband terahertz metamaterial electrical modulator

Journal Article 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · January 1, 2009 We demonstrate hybrid metamaterial devices that are able to electrically switch their resonances therefore the terahertz transmission properties at room temperature. The interrelated amplitude switching and phase shifting allow for fast broadband external ... Full text Cite

External modulation of terahertz quantum cascade lasers using electrically-driven active metamaterials

Journal Article 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · 2009 We have designed, fabricated and measured a first generation external modulator for a ∼2.4 terahertz Quantum Cascade Laser based on an electrically-driven active terahertz metamaterial structure. ©2008 Optical Society of America. ... Cite

Flexible wide angle terahertz resonant absorber based on perfectly impedance matched metamaterials

Journal Article 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009 · January 1, 2009 We present the design, fabrication and characterization of a highly flexible metamaterial absorber that experimentally obtains an absorptivity of 0.96 at 1.6 THz and operates over wide angular range for transverse electric and transverse magnetic radiation ... Full text Cite

Metamaterials for the terahertz gap

Conference 33rd International Conference on Infrared and Millimeter Waves and the 16th International Conference on Terahertz Electronics, 2008, IRMMW-THz 2008 · December 31, 2008 Metamaterials are engineered materials which offer superb electromagnetic performance over naturally occurring materials, and offer great potential to construct novel devices operating in the terahertz frequency regime. Here we experimentally demonstrate m ... Full text Cite

Active THz metamaterials

Conference 33rd International Conference on Infrared and Millimeter Waves and the 16th International Conference on Terahertz Electronics, 2008, IRMMW-THz 2008 · December 31, 2008 In this work, we demonstrate THz metamaterials exhibiting either amplitude control, via carrier injection or depletion in the active semiconductor substrate or frequency control, via photoexcitation of carriers into active semiconducting materials incorpor ... Full text Cite

Terahertz metamaterials on free-standing highly-flexible polyimide substrates

Journal Article Journal of Physics D: Applied Physics · December 1, 2008 We have fabricated resonant terahertz metamaterials on free-standing polyimide substrates. The low-loss polyimide substrates can be as thin as 5.5 νm yielding robust large-area metamaterials which are easily wrapped into cylinders with a radius of a few mi ... Full text Cite

Highly flexible wide angle of incidence terahertz metamaterial absorber: Design, fabrication, and characterization

Journal Article Physical Review B - Condensed Matter and Materials Physics · December 1, 2008 We present the design, fabrication, and characterization of a metamaterial absorber which is resonant at terahertz frequencies. We experimentally demonstrate an absorptivity of 0.97 at 1.6 THz. Importantly, our absorber is only 16 μm thick, resulting in a ... Full text Cite

Flexible terahertz metamaterials: Towards a terahertz metamaterial invisible cloak

Journal Article Technical Digest - International Electron Devices Meeting, IEDM · December 1, 2008 In this work, we present flexible metamaterials on free standing polyimide substrates operating at terahertz (THz) frequencies range. The successful demonstration of THz flexible metamaterials provides a path forward for creating multi-layer non-planar met ... Full text Cite

A dual-resonant terahertz metamaterial based on single-particle electric-field-coupled resonators

Journal Article Applied Physics Letters · November 21, 2008 We report the design, fabrication, and measurement of a terahertz metamaterial composed of single geometry electric field coupled resonators that has two closely spaced electric resonances near 1.0 and 1.5 THz. Due to the mutual coupling between the differ ... Full text Cite

Planar wallpaper group metamaterials for novel terahertz applications.

Journal Article Optics express · November 2008 We present novel metamaterial structures based upon various planar wallpaper groups, in both hexagonal and square unit cells. An investigation of metamaterials consisting of one, two, and three unique sub-lattices with resonant frequencies in the terahertz ... Full text Cite

Frequency tunable terahertz metamaterials

Conference Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · September 15, 2008 We present a hybrid metamaterial semiconductor device capable of 20% tunability of the center resonance frequency via photoexcitation of the semiconductor regions, thereby addressing the metamaterials drawback of narrow bandwidth operation. ©2008 Optical S ... Full text Cite

Flexible, large-area metamaterials fabricated on thin silicon nitride membranes

Journal Article 2008 Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro-Optics, CLEO/QELS · September 15, 2008 We present terahertz metamaterials fabricated on large-area, free-standing thin (≤1 μm) silicon nitride membranes with the aim of reducing dielectric losses, enhancing metamaterial sensing capabilities, and enabling flexible and conformable designs. © 2008 ... Full text Cite

Hybrid metamaterials enable fast electrical modulation of freely propagating terahertz waves

Journal Article Applied 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 ... Full text Cite

Dual-band planar electric THz metamaterial with resonator yield analysis

Journal Article Conference 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 ... Full text Cite

Dual-band planar electric THz metamaterial with resonator yield analysis

Journal Article 2008 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 ... Full text Cite

Sum rules and interlayer infrared response of the high temperature YBa2Cu3Oy superconductor in an external magnetic field.

Journal Article Physical review letters · August 2008 We present infrared magneto-optical measurements of the c-axis conductivity of YBa2Cu3Oy in both the underdoped (y=6.67 and 6.75) and optimally doped (y=6.95) regimes. We show that modest c-axis magnetic fields radically modify the condensate formation and ... Full text Cite

Dual-band planar electric metamaterial in the terahertz regime.

Journal Article Optics 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 ... Full text Cite

Experimental demonstration of frequency-agile terahertz metamaterials

Journal Article Nature Photonics · May 1, 2008 Metamaterials exhibit numerous novel effects and operate over a large portion of the electromagnetic spectrum. Metamaterial devices based on these effects include gradient-index lenses, modulators for terahertz radiation and compact waveguides. The resonan ... Full text Cite

A metamaterial absorber for the terahertz regime: design, fabrication and characterization.

Journal Article Optics express · May 2008 We present a metamaterial that acts as a strongly resonant absorber at terahertz frequencies. Our design consists of a bilayer unit cell which allows for maximization of the absorption through independent tuning of the electrical permittivity and magnetic ... Full text Cite

Perfect metamaterial absorber.

Journal Article Physical 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 ... Full text Cite

Opto-electronic control of terahertz metamaterials

Conference Proceedings of SPIE - The International Society for Optical Engineering · March 31, 2008 We demonstrate external control of metamaterials operating at terahertz frequencies. Through photodoping of semiconducting substrates, used to support metamaterial arrays, we show ultrafast switching times. New metamaterial "grids" are presented, which may ... Full text Cite

Dual-band planar electric THz metamaterial with resonator yield analysis

Journal Article Optics 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 ... Cite

Dual-band planar electric THz metamaterial with resonator yield analysis

Journal Article Optics 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 ... Cite

Filling the electromagnetic void - metamaterial devices for the THz gap

Conference PROCEEDINGS OF THE 2008 INTERNATIONAL WORKSHOP ON METAMATERIALS · January 1, 2008 Link to item Cite

Dynamical control of terahertz metamaterial resonance response using bimaterial cantilevers

Journal Article Progress in Electromagnetics Research Symposium · January 1, 2008 In this work, we report a novel method for the dynamical control of the resonant electrical response of terahertz (THz) metamaterials. Our approach is based on planar arrays of split-ring resonators (SRRs) coupled with microfabrication methods to create a ... Cite

External modulation of terahertz quantum cascade lasers using metamaterials

Journal Article Optics InfoBase Conference Papers · January 1, 2008 We use active metamaterials as external modulators for a 2.4 THz Quantum Cascade Laser. We present initial optical modulation results with the goal of designing an electricallydriven modulator. © 2008 Optical Society of America. ... Cite

Flexible, large-area metamaterials fabricated on thin silicon nitride membranes

Journal Article Optics InfoBase Conference Papers · January 1, 2008 We present terahertz metamaterials fabricated on large-area, free-standing thin (≤1 μm) silicon nitride membranes with the aim of reducing dielectric losses, enhancing metamaterial sensing capabilities, and enabling flexible and conformable designs. © 2008 ... Cite

Terahertz metamaterials on thin silicon nitride membranes

Journal Article Materials Research Society Symposium Proceedings · January 1, 2008 The terahertz (THz) region of the electromagnetic spectrum holds promise for spectroscopic imaging of illicit and hazardous materials, and chemical fingerprinting using moment of inertia vibrational transitions. Passive and active devices operating at THz ... Full text Cite

MEMS and metamaterials: A perfect marriage at terahertz frequencies

Conference Technical Digest - Solid-State Sensors, Actuators, and Microsystems Workshop · January 1, 2008 This paper reports our recent progress on creating active structures and devices to enhance the ability to manipulate and detect far-infrared, or terahertz (THz), radiation by combining electromagnetic metamaterials with MEMS technologies. We have designed ... Full text Cite

External modulation of terahertz quantum cascade lasers using metamaterials

Conference Optics InfoBase Conference Papers · January 1, 2008 We use active metamaterials as external modulators for a 2.4 THz Quantum Cascade Laser. We present initial optical modulation results with the goal of designing an electricallydriven modulator. © 2008 Optical Society of America. ... Full text Cite

Active terahertz metamaterial devices

Conference Optics InfoBase Conference Papers · January 1, 2008 We demonstrate THz metamaterials exhibiting either amplitude control, via carrier injection or depletion in the active semiconductor substrate or frequency control, via photoexcitation of carriers into active semiconducting materials incorporated into the ... Full text Cite

Terahertz switch/modulator based on metamaterials

Conference Conference on Lasers and Electro-Optics, 2007, CLEO 2007 · December 1, 2007 Real-time control of terahertz metamaterial has been experimentally demonstrated through an electrical approach. The THz switching and modulation capabilities are realized by the external voltage bias to a planar hybrid metamaterial-semiconductor structure ... Full text Cite

Properties of planar electric metamaterials for novel terahertz applications

Journal Article Journal of Nanoelectronics and Optoelectronics · December 1, 2007 Planar electric metamaterials are experimentally studied in transmission and reflection utilizing terahertz time-domain spectroscopy. Electrically resonant behavior is observed and provides an estimate of the frequency-dependent transmissivity, reflectivit ... Full text Cite

Properties of novel terahertz electric metamaterials

Conference Conference on Lasers and Electro-Optics, 2007, CLEO 2007 · December 1, 2007 Planar electric metamaterials are studied with terahertz time-domain spectroscopy in transmission and reflection. Energy absorption of 5-20% due to Ohmic losses within the metal patterning is observed at resonant frequencies. Finite-element simulations ver ... Full text Cite

Semiconductors: a new class of metamaterials.

Journal Article Nature materials · December 2007 Full text Cite

Active metamaterials: A novel approach to manipulate terahertz waves: Invited paper

Journal Article IRMMW-THz2007 - Conference Digest of the Joint 32nd International Conference on Infrared and Millimetre Waves, and 15th International Conference on Terahertz Electronics · December 1, 2007 Compared to the neighboring infrared and microwave regimes, the terahertz (1 THz = 1012 Hz) regime is still in need of fundamental technological advances. This derives, in part, from a paucity of naturally occurring materials with useful electronic or phot ... Cite

Metamaterials for novel terahertz and millimeter wave devices

Journal Article Conference Proceedings of the International Symposium on Signals, Systems and Electronics · December 1, 2007 We present experimental results of metamaterials operating at terahertz and mm-wave frequencies. Metamaterials consist of a single layer of 200nm thick gold on a doped or undoped semiconducting substrate. By optical and electronic doping of supporting semi ... Full text Cite

Terahertz metamaterial devices

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 2007 Compared to the neighboring infrared and microwave regions, the terahertz regime is still in need of fundamental technological advances. This derives, in part, from a paucity of naturally occurring materials with useful electronic or photonic properties at ... Full text Cite

Terahertz metamaterials for active, tunable, and dynamical devices

Conference Proceedings of SPIE - The International Society for Optical Engineering · November 19, 2007 Tunable electromagnetic metamaterials can be designed through the incorporation of semiconducting materials. We present theory, simulation, and experimental results of metamaterials operating at terahertz frequencies. Specific emphasis is placed on the dem ... Full text Cite

Interlayer electrodynamics and unconventional vortex state in Y Ba2 Cu3 Oy

Journal Article Physical Review B - Condensed Matter and Materials Physics · August 31, 2007 We report on the c -axis magneto-optical response of Y Ba2 Cu3 Oy (y=6.65 and 6.75) single crystals, with magnetic fields oriented both parallel and perpendicular to the Cu O2 planes. The dominant characteristic of the c -axis electrodynamics in the superc ... Full text Cite

Ultrafast optical switching of terahertz metamaterials fabricated on ErAs/GaAs nanoisland superlattices.

Journal Article Optics letters · June 2007 We demonstrate optical switching of electrically resonant terahertz planar metamaterials fabricated on ErAs/GaAs nanoisland superlattice substrates. Photoexcited charge carriers in the superlattice shunt the capacitive regions of the constituent elements, ... Full text Cite

Electromagnetic characterization of planar metamaterials by oblique angle spectroscopic measurements

Journal Article Physical 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 ... Full text Cite

Terahertz plasmonic composites.

Journal Article Physical review. E, Statistical, nonlinear, and soft matter physics · March 2007 The dielectric response of a polymer matrix composite can be substantially modified and tuned within a broad frequency band by integrating within the material an artificial plasmon medium composed of periodically distributed, very thin, electrically conduc ... Full text Cite

Group theoretical description of artificial electromagnetic metamaterials.

Journal Article Optics express · February 2007 Point group theoretical methods are used to determine the electromagnetic properties of metamaterials, based solely upon the symmetries of the underlying constituent particles. From the transformation properties of an electromagnetic (EM) basis under symme ... Full text Cite

Complementary planar terahertz metamaterials.

Journal Article Optics express · February 2007 Planar electric split ring resonator (eSRR) metamaterials and their corresponding inverse structures are designed and characterized computationally and experimentally utilizing finite element modeling and THz time domain spectroscopy. A complementary respo ... Full text Cite

Electrically resonant terahertz metamaterials: Theoretical and experimental investigations

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 25, 2007 We present a class of artificial materials that exhibit a tailored response to the electrical component of electromagnetic radiation. These electric metamaterials are investigated theoretically, computationally, and experimentally using terahertz time-doma ... Full text Cite

Metamaterials and their THz applications

Conference IRMMW-THz2007 - Conference Digest of the Joint 32nd International Conference on Infrared and Millimetre Waves, and 15th International Conference on Terahertz Electronics · January 1, 2007 We present experimental results of metamaterials operating at terahertz and mm-wave frequencies. Metamaterials consist of a single layer of 200nm thick gold on a doped or undoped semiconducting substrate. By optical and electronic doping of supporting semi ... Full text Cite

Metamaterials for Novel Terahertz and Millimeter Wave Devices

Conference 2007 INTERNATIONAL SYMPOSIUM ON SIGNALS, SYSTEMS AND ELECTRONICS, VOLS 1 AND 2 · January 1, 2007 Link to item Cite

Active metamaterials: a novel approach to manipulate terahertz waves

Conference 2007 JOINT 32ND INTERNATIONAL CONFERENCE ON INFRARED AND MILLIMETER WAVES AND 15TH INTERNATIONAL CONFERENCE ON TERAHERTZ ELECTRONICS, VOLS 1 AND 2 · January 1, 2007 Link to item Cite

Dynamically frequency tunable terahertz metamaterials

Journal Article Optics InfoBase Conference Papers · January 1, 2007 We present novel terahertz metamaterials that feature frequency tunable resonant responses. Tunability is achieved by selective patterning of semiconductor regions within split-ring resonator structures. Simulations reveal non-linear frequency tuning as a ... Cite

Electrical control of terahertz metamaterials

Journal Article Optics InfoBase Conference Papers · January 1, 2007 The metamaterials resonant response significantly enhances THz-wave/material interaction. We demonstrated real-time switchable THz metamaterial via external voltage bias to modify the metamaterial capacitive elements, thereby achieved effective control and ... Cite

Novel terahertz electric metamaterials

Journal Article Optics InfoBase Conference Papers · January 1, 2007 Planar electric metamaterials and their inverse structures are demonstrated to show complementary electrical resonant behavior in terahertz time-domain spectroscopy. Simulations and measured data agree well and illustrate potential applicability of these m ... Cite

Properties of novel terahertz electric metamaterials

Journal Article Optics InfoBase Conference Papers · 2007 Planar electric metamaterials are studied with terahertz time-domain spectroscopy in transmission and reflection. Energy absorption of 5-20% due to Ohmic losses within the metal patterning is observed at resonant frequencies. Finite-element simulations ver ... Cite

Split-ring resonator enhanced terahertz antenna

Journal Article Optics InfoBase Conference Papers · January 1, 2007 An electric split-ring resonator is used to enhance the performance of a photoconductive dipolar antenna based terahertz transmitter. Enhancement is observed near and limited to the resonant frequency of the electric split-ring resonator. © 2007 Optical So ... Cite

Terahertz switch/modulator based on metamaterials

Journal Article Optics InfoBase Conference Papers · 2007 Real-time control of terahertz metamaterial has been experimentally demonstrated through an electrical approach. The THz switching and modulation capabilities are realized by the external voltage bias to a planar hybrid metamaterial-semiconductor structure ... Cite

Novel terahertz electric metamaterials

Conference Optics InfoBase Conference Papers · January 1, 2007 Planar electric metamaterials and their inverse structures are demonstrated to show complementary electrical resonant behavior in terahertz time-domain spectroscopy. Simulations and measured data agree well and illustrate potential applicability of these m ... Full text Cite

Electrical control of terahertz metamaterials

Conference Optics InfoBase Conference Papers · January 1, 2007 The metamaterials resonant response significantly enhances THz-wave/material interaction. We demonstrated real-time switchable THz metamaterial via external voltage bias to modify the metamaterial capacitive elements, thereby achieved effective control and ... Full text Cite

Split-ring resonator enhanced terahertz antenna

Conference Optics InfoBase Conference Papers · January 1, 2007 An electric split-ring resonator is used to enhance the performance of a photoconductive dipolar antenna based terahertz transmitter. Enhancement is observed near and limited to the resonant frequency of the electric split-ring resonator. © 2007 Optical So ... Full text Cite

Dynamically frequency tunable terahertz metamaterials

Conference Optics InfoBase Conference Papers · January 1, 2007 We present novel terahertz metamaterials that feature frequency tunable resonant responses. Tunability is achieved by selective patterning of semiconductor regions within split-ring resonator structures. Simulations reveal non-linear frequency tuning as a ... Full text Cite

Infrared probe of the anomalous magnetotransport of highly oriented pyrolytic graphite in the extreme quantum limit

Journal Article Physical Review B - Condensed Matter and Materials Physics · November 10, 2006 We present a systematic investigation of the magnetoreflectance R(ω,B) of highly oriented pyrolytic graphite in magnetic field B up to 18 T. From these measurements, we report the determination of lifetimes τ associated with the lowest Landau levels in the ... Full text Cite

Active terahertz metamaterial devices.

Journal Article Nature · November 2006 The development of artificially structured electromagnetic materials, termed metamaterials, has led to the realization of phenomena that cannot be obtained with natural materials. This is especially important for the technologically relevant terahertz (1 T ... Full text Cite

Calculation and measurement of bianisotropy in a split ring resonator metamaterial

Journal Article Journal 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 ... Full text Cite

Negative refractive index metamaterials

Journal Article Materials 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 ... Full text Cite

Dynamical electric and magnetic metamaterial response at terahertz frequencies.

Journal Article Physical review letters · March 2006 Utilizing terahertz time domain spectroscopy, we have characterized the electromagnetic response of a planar array of split ring resonators (SRRs) fabricated upon a high resistivity GaAs substrate. The measured frequency dependent magnetic and electric res ... Full text Cite

Dynamical metamaterials at terahertz frequencies

Conference Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS · January 1, 2006 Utilizing terahertz time domain spectroscopy, we characterized the electromagnetic response of planar Split Ring Resonators fabricated on GaAs. Optical excitation is sufficient to turn off the electric resonance demonstrating the potential of SRR terahertz ... Full text Cite

Dynamical electric and magnetic metamaterial response at terahertz frequencies

Journal Article Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006 · January 1, 2006 Utilizing terahertz time domain spectroscopy, we characterized the electromagnetic response of planar Split Ring Resonators fabricated on GaAs. Optical excitation is sufficient to turn off the electric resonance demonstrating the potential of SRR terahertz ... Full text Cite

Dynamical electric metamaterial response at terahertz frequencies

Journal Article Optics InfoBase Conference Papers · January 1, 2006 Utilizing terahertz time domain spectroscopy, we characterized the electromagnetic response of planar Split Ring Resonators fabricated on GaAs. Optical excitation is sufficient to turn off the electric resonance demonstrating the potential of SRR terahertz ... Full text Cite

Dynamical electric metamaterial response at Terahertz frequencies

Journal Article Optics InfoBase Conference Papers · January 1, 2006 Utilizing terahertz time domain spectroscopy, we characterized the electromagnetic response of planar Split Ring Resonators fabricated on GaAs. Optical excitation is sufficient to turn off the electric resonance demonstrating the potential of SRR terahertz ... Full text Cite

Novel electrically resonant terahertz metamaterials

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We present new designs for metamaterials that exhibit a tailored resonant electrical response, investigated with THz time domain spectroscopy. These electric metamaterials will significantly ease the burden of construction for future negative index metamat ... Cite

Novel electrically resonant terahertz metamaterials

Conference Optics InfoBase Conference Papers · January 1, 2006 We present new designs for metamaterials that exhibit a tailored resonant electrical response, investigated with THz time domain spectroscopy. These electric metamaterials will significantly ease the burden of construction for future negative index metamat ... Full text Cite

Spectroscopy of metamaterials from infrared top optical frequencies

Journal Article Journal 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 ... Full text Cite

Fabrication and optical measurements of nanoscale meta-materials: Terahertz and beyond

Journal Article The Joint 30th International Conference on Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics, 2005. IRMMW-THz 2005 · December 1, 2005 Cite

Infrared signatures of hole and spin stripes in La2-xSrxCuO4

Journal Article Physical Review B - Condensed Matter and Materials Physics · November 15, 2005 We investigate the hole and lattice dynamics in a prototypical high-temperature superconducting system La2-xSrxCuO4 using infrared spectroscopy. By exploring the anisotropy in the electronic response of CuO2 planes we show that our results support the noti ... Full text Cite

Strong-coupling effects in cuprate high-Tc superconductors by magneto-optical studies

Journal Article Physical Review B - Condensed Matter and Materials Physics · November 1, 2005 Signatures of strong coupling effects in cuprate high-Tc superconductors have been authenticated through a variety of spectroscopic probes. However, the microscopic nature of relevant excitations has not been agreed upon. Here, we report on magneto-optical ... Full text Cite

Constant effective mass across the phase diagram of high- Tc cuprates

Journal Article Physical Review B - Condensed Matter and Materials Physics · August 1, 2005 We investigate the hole dynamics in two prototypical high temperature superconducting systems: La2-x Srx Cu O4 and Y Ba2 Cu3 Oy, using a combination of dc transport and infrared spectroscopy. By exploring the effective spectral weight obtained with optics ... Full text Cite

Electrodynamics of the nodal metal state in weakly doped high- Tc cuprates

Journal Article Physical Review B - Condensed Matter and Materials Physics · August 1, 2005 We report on the detailed analysis of the infrared (IR) conductivity of two prototypical high- Tc systems Y Ba2 Cu3 Oy and La2-x Srx Cu O4 throughout the complex phase diagram of these compounds. Our focus in this work is to thoroughly document the electro ... Full text Cite

Infrared spectroscopy and ellipsometry of magnetic metamaterials

Journal Article Progress 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 ... Full text Cite

Broadband multi-interferometer spectroscopy in high magnetic fields: From THz to visible

Journal Article Review of Scientific Instruments · November 1, 2004 We present a system capable of broad band frequency domain spectroscopy in the range 6-20 000 cm -1 at cryogenic temperatures. The apparatus couples two different interferometers to a 9 Tesla superconducting split coil magnet and is designed to work with v ... Full text Cite

Terahertz magnetic response from artificial materials.

Journal Article Science (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 ... Full text Cite

Subterahertz spectroscopy at He-3 temperatures

Journal Article Review of Scientific Instruments · November 1, 2003 The design and implementation of a sub-THz spectrometer for operations at temperatures down to 340 mK was demonstrated. A Martin-Puplett (MP) interferometer was coupled to a cryostat housing two independently controlled platforms cooled down with He-3 for ... Full text Cite

Terahertz plasmonic high pass filter

Journal Article Applied 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 ... Full text Cite

Ferromagnetic resonance in double perovskite Ba2FeMoO6

Conference Journal of Magnetism and Magnetic Materials · January 1, 2003 In this work the study of the ferromagnetic resonance and of the electrical conductivity in the perovskite sample, Ba2FeMoO6, is presented. Double perovskite has been manufactured by conventional ceramic method sintering in an inert gas atmosphere. Electri ... Full text Cite

Artificial plasmonic metamaterial fabricated by micro-stereolithography

Journal Article American 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 ... Full text Cite

Searching for the Slater transition in the pyrochlore Cd2Os2O7 with infrared spectroscopy

Journal Article Physical Review B - Condensed Matter and Materials Physics · July 15, 2002 Infrared reflectance measurements were made on the single crystal pyrochlore Cd2Os2O7 in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal-insulator transition (MIT) at TMIT=226 K. All pre ... Full text Cite

Searching for the Slater transition in the pyrochlore Cd2Os2O7 with infrared spectroscopy

Journal Article Physical Review B - Condensed Matter and Materials Physics · July 15, 2002 Infrared reflectance measurements were made on the single crystal pyrochlore Cd2Os2O7 in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal-insulator transition (MIT) at TMIT=226 K. All pre ... Cite

Fabrication and characterization of THz plasmonic filter

Conference Proceedings of the IEEE Conference on Nanotechnology · January 1, 2002 Terahertz imaging systems have applications for explosives detection, aircraft guidance and landing in zero-visibility weather condition, as well as terrestrial and astronomical remote sensing. These critical applications need a variety of optical elements ... Full text Cite

Searching for the Slater transition in the pyrochlore Cd2Os2O7 with infrared spectroscopy

Journal Article Physical Review B - Condensed Matter and Materials Physics · 2002 Infrared reflectance measurements were made on the single crystal pyrochlore Cd2Os2O7 in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal-insulator transition (MIT) at TMIT=226 K. All pre ... Cite

Left-handed metamaterials

Conference PHOTONIC CRYSTALS AND LIGHT LOCALIZATION IN THE 21ST CENTURY · January 1, 2001 Link to item Cite

Composite medium with simultaneously negative permeability and permittivity

Journal Article Physical 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 ... Full text Cite

Negative permeability from split ring resonator arrays

Journal Article Conference 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 ... Cite

Loop-wire medium for investigating plasmons at microwave frequencies

Journal Article Applied 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 ... Full text Cite