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Michael E. Gehm

Professor of Electrical and Computer Engineering
Electrical and Computer Engineering
Box 90291, Durham, NC 27708
3463 Ciemas, Fitzpatrick Center, Durham, NC 27708

Selected Publications


A high resolution miniature electron energy spectrometer

Journal Article Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment · July 1, 2024 In this work we describe how a novel mass spectrometer design we recently reported on can be utilized as an electron spectrometer having excellent resolution and passband width. This new electron spectrometer is referred to as a segmented electrode electro ... Full text Cite

Spectral Reconstruction Improvement in a Cycloidal Coded-Aperture Mass Spectrometer.

Journal Article Journal of the American Society for Mass Spectrometry · May 2024 Spatial aperture coding is a technique used to improve throughput without sacrificing resolution both in optical spectroscopy and sector mass spectrometry (MS). Previous work demonstrated that aperture coding combined with a position-sensitive array detect ... Full text Cite

Toward One-Way Smoke: Synthesis of Copper-Based Microclubs with Asymmetric Scattering and Absorption

Journal Article Advanced Functional Materials · January 1, 2024 The ultimate goal of this work is to create an engineered aerosol that acts as one-way smoke, i.e. it creates an asymmetric vision environment in which the ability to image objects depends on the viewing direction. To this end, a rapid, one-pot synthesis o ... Full text Cite

A super-resolution proof of concept in a cycloidal coded aperture miniature mass spectrometer.

Journal Article Rapid communications in mass spectrometry : RCM · January 2023 RationaleHigher resolution in fieldable mass spectrometers (MS) is desirable in space flight applications to enable resolving isobaric interferences at m/z < 60 u. Resolution in portable cycloidal MS coupled with array detectors could be improved ... Full text Cite

Performance of a high-throughput full-tunnel XRD checked baggage scanning system

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 X-ray diffraction imaging (XRDI) offers the potential for reduced false alarm rates, increased throughputs, and more sensitive explosives detection performance in aviation security applications. The deployment of computed tomography (CT) systems across car ... Full text Cite

Simulation and information-theoretic analysis of a hybrid CT+XRD imaging system

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Simulation is a valuable tool for designing and evaluating the performance of x-ray imaging systems. In previous work,1, 2 a hybrid computed tomography(CT) and x-ray diffraction(XRD) imaging system was developed for improved identification of threat object ... Full text Cite

Spectrally Responsive Edge Illumination X-ray Phase Contrast Imaging (XPCI)

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 X-ray Phase Contrast Imaging (XPCI) is an imaging method used to retrieve phase information from an object, thereby revealing more object characteristics, such as refractive index and thickness. Edge Illumination (EI) is a non-interferometric type of XPCI ... Full text Cite

Asymmetric Illumination X-Ray Differential Phase Contrast Imaging

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 X-ray phase contrast imaging has the potential to improve image contrast and better differentiate between weakly attenuating materials. Current implementations, however, focus on small biological samples and coherent sources. Here we propose asymmetric ill ... Full text Cite

Imaging asymmetry in the presence of a bright interferent

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Previously, Alyones et. al. (Appl Opt. 54 (2015)),1 showed that a pair of aerosol plumes — one purely scattering, the other purely absorbing—in the presence of a bright interferent, had the interesting property that the imaging contrast ratios through the ... Full text Cite

Towards creation of an asymmetric vision environment

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Airborne scattering media, such as fog, obstructs imaging by destroying the one-to-one object to image mapping relationship through a multiple scattering process. Existing research in this area is predicated on developing methods to image despite this scat ... Full text Cite

Design considerations for a cycloidal mass analyzer using a focal plane array detector.

Journal Article Journal of mass spectrometry : JMS · July 2022 With the advent of technologies such as ion array detectors and high energy permanent magnet materials, there is renewed interest in the unique focusing properties of the cycloidal mass analyzer and its ability to enable small, high-resolution, and high-se ... Full text Cite

Characterization of photon counting detectors for x-ray diffraction (XRD) applications

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2022 Photon counting detectors with energy resolving capabilities have the potential to improve computed tomography (CT) imaging and x-ray diffraction (XRD) systems. In order to better understand the use of these detectors in the CT and XRD application spaces, ... Full text Cite

Spectrally responsive edge-illumination (SREI) x-ray phase contrast imaging (XPCI)

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2022 X-ray Phase Contrast Imaging (XPCI) is an imaging method that can provide quantitative information about the change in phase of X-ray wavefronts as they pass through an object. XPCI can image objects that cannot be easily seen in conventional absorption im ... Full text Cite

The Long Neglected Cycloidal Mass Analyzer.

Journal Article Analytical chemistry · August 2021 In 1938, Walker Bleakney and John A. Hipple first described the cycloidal mass analyzer as the only mass analyzer configuration capable of "perfect" ion focusing. Why has their geometry been largely neglected for many years and how might it earn a respecta ... Full text Cite

Improving the Performance of a Cycloidal Coded-Aperture Miniature Mass Spectrometer.

Journal Article Journal of the American Society for Mass Spectrometry · February 2021 Cycloidal sector mass analyzers have, in principle, perfect focusing due to perpendicularly oriented uniform electric and magnetic fields, making them ideal candidates for incorporation of spatially coded apertures. We have previously demonstrated a proof- ... Full text Cite

Design and analysis of a hybrid X-ray transmission and diffraction system

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2021 Aviation security, mail inspection, medical diagnostics and many other industries all face the same challenge: to accurately identify the presence of a target material concealed within a cluttered surrounding environment. X-ray systems that combine transmi ... Full text Cite

Comparison of thermionic filament and carbon nanotube field emitter-based electron ionization sources in cycloidal coded aperture mass analyzers

Journal Article International Journal of Mass Spectrometry · November 1, 2020 This work compares the coded aperture imaging performance of thermionic filament and carbon nanotube (CNT) field emitter-based electron sources in cycloidal-coded aperture mass spectrometers. The use of spatially coded apertures in mass spectrometry enable ... Full text Cite

Resolution and sampling analysis in digital in-line holography with spherical wave illumination

Journal Article Optical Engineering · October 1, 2020 The resolution optimization and sampling strategies in practical digital in-line holography (DIH) with spherical wave illumination are analytically studied by optimizing system parameters. Optimal parameters of holographic recording, including illumination ... Full text Cite

A novel sector mass spectrograph design for high-order coded aperture Mass Spectrometry with stigmatic aberration correction

Journal Article International Journal of Mass Spectrometry · September 1, 2020 Previous works experimentally demonstrated that the application of spatially-coded apertures to simple sector mass spectrographs can result in increased signal intensity while maintaining spectral resolution comparable to that of a conventional slit apertu ... Full text Cite

The all-seeing baggage scanner

Journal Article IEEE Spectrum · July 1, 2020 Full text Cite

A high resolution miniature electron energy spectrometer

Journal Article Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment · July 1, 2024 In this work we describe how a novel mass spectrometer design we recently reported on can be utilized as an electron spectrometer having excellent resolution and passband width. This new electron spectrometer is referred to as a segmented electrode electro ... Full text Cite

Spectral Reconstruction Improvement in a Cycloidal Coded-Aperture Mass Spectrometer.

Journal Article Journal of the American Society for Mass Spectrometry · May 2024 Spatial aperture coding is a technique used to improve throughput without sacrificing resolution both in optical spectroscopy and sector mass spectrometry (MS). Previous work demonstrated that aperture coding combined with a position-sensitive array detect ... Full text Cite

Toward One-Way Smoke: Synthesis of Copper-Based Microclubs with Asymmetric Scattering and Absorption

Journal Article Advanced Functional Materials · January 1, 2024 The ultimate goal of this work is to create an engineered aerosol that acts as one-way smoke, i.e. it creates an asymmetric vision environment in which the ability to image objects depends on the viewing direction. To this end, a rapid, one-pot synthesis o ... Full text Cite

A super-resolution proof of concept in a cycloidal coded aperture miniature mass spectrometer.

Journal Article Rapid communications in mass spectrometry : RCM · January 2023 RationaleHigher resolution in fieldable mass spectrometers (MS) is desirable in space flight applications to enable resolving isobaric interferences at m/z < 60 u. Resolution in portable cycloidal MS coupled with array detectors could be improved ... Full text Cite

Performance of a high-throughput full-tunnel XRD checked baggage scanning system

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 X-ray diffraction imaging (XRDI) offers the potential for reduced false alarm rates, increased throughputs, and more sensitive explosives detection performance in aviation security applications. The deployment of computed tomography (CT) systems across car ... Full text Cite

Simulation and information-theoretic analysis of a hybrid CT+XRD imaging system

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Simulation is a valuable tool for designing and evaluating the performance of x-ray imaging systems. In previous work,1, 2 a hybrid computed tomography(CT) and x-ray diffraction(XRD) imaging system was developed for improved identification of threat object ... Full text Cite

Spectrally Responsive Edge Illumination X-ray Phase Contrast Imaging (XPCI)

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 X-ray Phase Contrast Imaging (XPCI) is an imaging method used to retrieve phase information from an object, thereby revealing more object characteristics, such as refractive index and thickness. Edge Illumination (EI) is a non-interferometric type of XPCI ... Full text Cite

Asymmetric Illumination X-Ray Differential Phase Contrast Imaging

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 X-ray phase contrast imaging has the potential to improve image contrast and better differentiate between weakly attenuating materials. Current implementations, however, focus on small biological samples and coherent sources. Here we propose asymmetric ill ... Full text Cite

Imaging asymmetry in the presence of a bright interferent

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Previously, Alyones et. al. (Appl Opt. 54 (2015)),1 showed that a pair of aerosol plumes — one purely scattering, the other purely absorbing—in the presence of a bright interferent, had the interesting property that the imaging contrast ratios through the ... Full text Cite

Towards creation of an asymmetric vision environment

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2023 Airborne scattering media, such as fog, obstructs imaging by destroying the one-to-one object to image mapping relationship through a multiple scattering process. Existing research in this area is predicated on developing methods to image despite this scat ... Full text Cite

Design considerations for a cycloidal mass analyzer using a focal plane array detector.

Journal Article Journal of mass spectrometry : JMS · July 2022 With the advent of technologies such as ion array detectors and high energy permanent magnet materials, there is renewed interest in the unique focusing properties of the cycloidal mass analyzer and its ability to enable small, high-resolution, and high-se ... Full text Cite

Characterization of photon counting detectors for x-ray diffraction (XRD) applications

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2022 Photon counting detectors with energy resolving capabilities have the potential to improve computed tomography (CT) imaging and x-ray diffraction (XRD) systems. In order to better understand the use of these detectors in the CT and XRD application spaces, ... Full text Cite

Spectrally responsive edge-illumination (SREI) x-ray phase contrast imaging (XPCI)

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2022 X-ray Phase Contrast Imaging (XPCI) is an imaging method that can provide quantitative information about the change in phase of X-ray wavefronts as they pass through an object. XPCI can image objects that cannot be easily seen in conventional absorption im ... Full text Cite

The Long Neglected Cycloidal Mass Analyzer.

Journal Article Analytical chemistry · August 2021 In 1938, Walker Bleakney and John A. Hipple first described the cycloidal mass analyzer as the only mass analyzer configuration capable of "perfect" ion focusing. Why has their geometry been largely neglected for many years and how might it earn a respecta ... Full text Cite

Improving the Performance of a Cycloidal Coded-Aperture Miniature Mass Spectrometer.

Journal Article Journal of the American Society for Mass Spectrometry · February 2021 Cycloidal sector mass analyzers have, in principle, perfect focusing due to perpendicularly oriented uniform electric and magnetic fields, making them ideal candidates for incorporation of spatially coded apertures. We have previously demonstrated a proof- ... Full text Cite

Design and analysis of a hybrid X-ray transmission and diffraction system

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2021 Aviation security, mail inspection, medical diagnostics and many other industries all face the same challenge: to accurately identify the presence of a target material concealed within a cluttered surrounding environment. X-ray systems that combine transmi ... Full text Cite

Comparison of thermionic filament and carbon nanotube field emitter-based electron ionization sources in cycloidal coded aperture mass analyzers

Journal Article International Journal of Mass Spectrometry · November 1, 2020 This work compares the coded aperture imaging performance of thermionic filament and carbon nanotube (CNT) field emitter-based electron sources in cycloidal-coded aperture mass spectrometers. The use of spatially coded apertures in mass spectrometry enable ... Full text Cite

Resolution and sampling analysis in digital in-line holography with spherical wave illumination

Journal Article Optical Engineering · October 1, 2020 The resolution optimization and sampling strategies in practical digital in-line holography (DIH) with spherical wave illumination are analytically studied by optimizing system parameters. Optimal parameters of holographic recording, including illumination ... Full text Cite

A novel sector mass spectrograph design for high-order coded aperture Mass Spectrometry with stigmatic aberration correction

Journal Article International Journal of Mass Spectrometry · September 1, 2020 Previous works experimentally demonstrated that the application of spatially-coded apertures to simple sector mass spectrographs can result in increased signal intensity while maintaining spectral resolution comparable to that of a conventional slit apertu ... Full text Cite

The all-seeing baggage scanner

Journal Article IEEE Spectrum · July 1, 2020 Full text Cite

Task-specific information in X-ray diffraction and transmission modalities: A comparative analysis

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2020 We develop a framework to analyze the information content of X-ray measurement data for the task of material discrimination. This task-specific information (TSI) analysis provides valuable information for system design and optimization. We employ Bhattacha ... Full text Cite

Modeling realistic virtual objects within a high-throughput X-ray simulation framework

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2020 X-ray simulation of realistic object models is relevant across all areas in which X-ray systems are employed, including medical, industrial, and security applications. A particularly exciting area of impact stems from the development of machine learning ap ... Full text Cite

Single-shot multispectral imaging through a thin scatterer

Journal Article Optica · July 20, 2019 BACKGROUND: Performing imaging with scattered light is challenging due to the complex and random modulation imposed upon the light by the scatterer. Persistent correlations, such as the optical memory effect (ME), enable high-fidelity, diffractionlimited i ... Full text Cite

Rapid simulation of X-ray scatter measurements for threat detection via GPU-based ray-tracing

Journal Article Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms · June 15, 2019 Scatter-based X-ray imaging has increased in prominence in areas ranging from cancer diagnostics to threat detection in aviation security, due largely to the development of new algorithms and components over the last decade. However, system design and algo ... Full text Cite

Terahertz radiation of a butterfly-shaped photoconductive antenna(invited)

Journal Article Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering · April 25, 2019 The terahertz(THz) far-field radiation properties of a butterfly-shaped photoconductive antenna (PCA) were experimentally studied using a home-built THz time-domain spectroscopy(THz-TDS) setup. To distinguish the contribution of in -gap photocurrent and an ... Full text Cite

Three-dimensionally-printed anthropomorphic physical phantom for mammography and digital breast tomosynthesis with custom materials, lesions, and uniform quality control region.

Journal Article J Med Imaging (Bellingham) · April 2019 Anthropomorphic breast phantoms mimic patient anatomy in order to evaluate clinical mammography and digital breast tomosynthesis system performance. Our goal is to create a modular phantom with an anthropomorphic region to allow for improved lesion and cal ... Full text Link to item Cite

Using inkjet 3D printing to create contrast-enhanced textured physical phantoms for CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2019 Anthropomorphic phantoms can serve as anatomically structured tools for assessing clinical computed tomography (CT) imaging systems. The aim of this project is to create highly customized 3D inkjet-printed, contrast-enhanced physical liver phantoms for use ... Full text Cite

Modeling real world system geometry and detector response within a high-throughput X-ray simulation framework

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2019 Simulations of x-ray scanners have the potential to aid in the design and understanding of system performance. We have previously shown the usefulness of a high-throughput simulation framework in pursuit of information theoretic analysis of x-ray systems e ... Full text Cite

Motivations and methods for the analysis of multi-modality X-ray systems for explosives detection

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2019 Transmission-based imaging and X-ray diffraction-based material analysis have largely developed independently. However, for a variety of applications ranging from in-vivo soft tissue analysis to concealed explosives detection, it is necessary to realize hi ... Full text Cite

Simulation-based X-ray system design and analysis: Past, present, and future

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2019 Since 2013, a Duke University / University of Arizona collaboration has been investigating how to optimize the hardware design of aviation-security x-ray systems. The goal of the effort is to develop a detection-algorithmagnostic approach that focuses on t ... Full text Cite

Prototype coded aperture miniature mass spectrometer for environmental sensing

Conference AQM 2019 - Air Quality Measurement Methods and Technology Conference 2019 · January 1, 2019 © 2019 Air and Waste Management Association. All rights reserved. In summary, this paper shows the design and initial performance characterization of a coded aperture miniature mass spectrometer for environmental sensing (CAMMS-ES). CAMMS-ES incorporates s ... Cite

Prototype coded aperture miniature mass spectrometer for environmental sensing

Conference AQM 2019 - Air Quality Measurement Methods and Technology Conference 2019 · January 1, 2019 In summary, this paper shows the design and initial performance characterization of a coded aperture miniature mass spectrometer for environmental sensing (CAMMS-ES). CAMMS-ES incorporates spatial aperture coding to break the throughput vs. resolution trad ... Cite

Single-shot multispectral color imaging through scattering media

Conference Optics InfoBase Conference Papers · January 1, 2019 Memory effect (ME) imaging forms high-fidelity, diffraction-limited images through scatter without any prior knowledge. Here we demonstrate compressive ME imaging by extracting a color image of a scatter-obscured object from a single coded monochrome expos ... Full text Cite

Multi-carrier channeled polarimetry for photoelastic modulator systems.

Journal Article Optics letters · December 2018 Photoelastic modulator-based polarimeters use multi-carrier modulation schemes that are more complicated than the single carriers of rotating optics. Current state-of-the-art reconstruction implementations favor mathematical simplicity by using significant ... Full text Cite

Single-shot memory-effect video.

Journal Article Scientific reports · September 2018 Imaging through opaque scattering media is critically important in applications ranging from biological and astronomical imaging to metrology and security. While the random process of scattering in turbid media produces scattered light that appears uninfor ... Full text Cite

Prototype coded aperture miniature mass spectrometer using a cycloidal sector mass analyzer

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · August 19, 2018 Link to item Cite

Implementing Sparse Sub-Sampling Methods for Low-Dose/High Speed STEM

Journal Article Microscopy and Microanalysis · August 2018 Full text Cite

Proof of Concept Coded Aperture Miniature Mass Spectrometer Using a Cycloidal Sector Mass Analyzer, a Carbon Nanotube (CNT) Field Emission Electron Ionization Source, and an Array Detector.

Journal Article Journal of the American Society for Mass Spectrometry · February 2018 Despite many potential applications, miniature mass spectrometers have had limited adoption in the field due to the tradeoff between throughput and resolution that limits their performance relative to laboratory instruments. Recently, a solution to this tr ... Full text Cite

Effects of Magnetic and Electric Field Uniformity on Coded Aperture Imaging Quality in a Cycloidal Mass Analyzer.

Journal Article Journal of the American Society for Mass Spectrometry · February 2018 Cycloidal mass analyzers are unique sector mass analyzers as they exhibit perfect double focusing, making them ideal for incorporating spatial aperture coding, which can increase the throughput of a mass analyzer without affecting the resolving power. Howe ... Full text Cite

A sub-sampled approach to extremely low-dose STEM

Journal Article Applied Physics Letters · January 22, 2018 The inpainting of deliberately and randomly sub-sampled images offers a potential means to image specimens at a high resolution and under extremely low-dose conditions (≤1 e-/Å2) using a scanning transmission electron microscope. We show that deliberate su ... Full text Cite

Rapid simulation of X-ray transmission imaging for baggage inspection via GPU-based ray-tracing

Journal Article Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms · January 15, 2018 We present a pipeline that rapidly simulates X-ray transmission imaging for arbitrary system architectures using GPU-based ray-tracing techniques. The purpose of the pipeline is to enable statistical analysis of threat detection in the context of airline b ... Full text Cite

3D printed anthropomorphic physical phantom for mammography and DBT with high contrast custom materials, lesions, and uniform chest wall region

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018 Anthropomorphic breast phantoms mimic anatomy to evaluate the performance of clinical mammography and digital breast tomosynthesis (DBT) systems. Our goal is to make a phantom that mimics clinically relevant appearance of a patient to allow for improved im ... Full text Cite

Channel-first design of modulated polarimeters

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2018 Multi-domain modulated polarimeters combine carriers on different domains to exploit the bandwidth of the measurement system. However, the inevitable systematic errors in polarimeters will degrade their bandwidth performance, so we developed a new type of ... Full text Cite

An information theoretic approach to system optimization accounting for material variability

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2018 Differentiating material anomalies requires a measurement system that can reliably inform the user/classifier of pertinent material characteristics. In past work, we have developed a simulation framework capable of making simulated x-ray transmission and s ... Full text Cite

Model-Based Multiscale Gigapixel Image Formation Pipeline on GPU

Journal Article IEEE Transactions on Computational Imaging · September 2017 Full text Cite

Compressive Classification for TEM-EELS

Journal Article Microscopy and Microanalysis · July 2017 Full text Cite

Coded Apertures in Mass Spectrometry.

Journal Article Annual review of analytical chemistry (Palo Alto, Calif.) · June 2017 The use of coded apertures in mass spectrometry can break the trade-off between throughput and resolution that has historically plagued conventional instruments. Despite their very early stage of development, coded apertures have been shown to increase thr ... Full text Cite

Third generation anthropomorphic physical phantom for mammography and DBT: Incorporating voxelized 3D printing and uniform chest wall QC region

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2017 Physical breast phantoms provide a standard method to test, optimize, and develop clinical mammography systems, including new digital breast tomosynthesis (DBT) systems. In previous work, we produced an anthropomorphic phantom based on 500x500x500 μm breas ... Full text Cite

Creating an experimental testbed for information-theoretic analysis of architectures for x-ray anomaly detection

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2017 Anomaly detection requires a system that can reliably convert measurements of an object into knowledge about that object. Previously, we have shown that an information-theoretic approach to the design and analysis of such systems provides insight into syst ... Full text Cite

Dynamically coded memory effect imaging

Conference Optics InfoBase Conference Papers · January 1, 2017 The optical memory effect has recently been used to image static scenes through opaque media. By using spatio-temporal coding, we realize memory effect video of dynamic scenes from a single, compressive measurement. ... Full text Cite

Image reconstruction for view-limited x-ray CT in baggage scanning

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2017 X-ray CT based baggage scanners are widely used in security applications. Recently, there has been increased interest in view-limited systems which can improve the scanning throughput while maintaining the threat detection performance. However as very few ... Full text Cite

Experimental demonstration of an adaptive architecture for direct spectral imaging classification.

Journal Article Optics express · August 2016 Spectral imaging is a powerful tool for providing in situ material classification across a spatial scene. Typically, spectral imaging analyses are interested in classification, though often the classification is performed only after reconstruction of the s ... Full text Cite

Shape threat detection via adaptive computed tomography

Conference SPIE Proceedings · May 12, 2016 Full text Cite

Aviation security x-ray detection challenges

Conference SPIE Proceedings · May 12, 2016 Full text Cite

Direction of arrival (DOA) estimation system using 3D printed Luneburg lens

Conference 2016 IEEE/ACES International Conference on Wireless Information Technology, ICWITS 2016 and System and Applied Computational Electromagnetics, ACES 2016 - Proceedings · May 4, 2016 A novel direction of arrival (DOA) estimation system based on a broadband 3D printed Luneburg lens is reported in this paper. Using the property of a Luneburg lens that the focus point of an incident plane wave is at the opposite side on the surface of the ... Full text Cite

Compatibility of Spatially Coded Apertures with a Miniature Mattauch-Herzog Mass Spectrograph.

Journal Article Journal of the American Society for Mass Spectrometry · April 2016 In order to minimize losses in signal intensity often present in mass spectrometry miniaturization efforts, we recently applied the principles of spatially coded apertures to magnetic sector mass spectrometry, thereby achieving increases in signal intensit ... Full text Cite

Design, fabrication, and implementation of voxel-based 3D printed textured phantoms for task-based image quality assessment in CT

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 In x-ray computed tomography (CT), task-based image quality studies are typically performed using uniform background phantoms with low-contrast signals. Such studies may have limited clinical relevancy for modern non-linear CT systems due to possible influ ... Full text Cite

Second generation anthropomorphic physical phantom for mammography and DBT: Incorporating voxelized 3D printing and inkjet printing of iodinated lesion inserts

Conference Progress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2016 Physical phantoms are needed for the evaluation and optimization of new digital breast tomosynthesis (DBT) systems. Previously, we developed an anthropomorphic phantom based on human subject breast CT data and fabricated using commercial 3D printing. We no ... Full text Cite

Information-theoretic analysis of x-ray photoabsorption based threat detection system for check-point

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 In this work we present an information-theoretic framework for a systematic study of checkpoint x-ray systems using photoabsorption measurements. Conventional system performance analysis of threat detection systems confounds the effect of the system archit ... Full text Cite

Rapid GPU-based simulation of x-ray transmission, scatter, and phase measurements for threat detection systems

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 To support the statistical analysis of x-ray threat detection, we developed a very high-throughput x-ray modeling framework based upon GPU technologies and have created three different versions focusing on transmission, scatter, and phase. The simulation o ... Full text Cite

Information-theoretic analysis of x-ray scatter and phase architectures for anomaly detection

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 Conventional performance analysis of detection systems confounds the effects of the system architecture (sources, detectors, system geometry, etc.) with the effects of the detection algorithm. Previously, we introduced an information-theoretic approach to ... Full text Cite

Adaptive architectures for spectral processing

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 Introduction of adaptive components into optical sensing architectures can facilitate powerful new modes of operation that blend acquisition and exploitation. I discuss three spectral applications where such gains have been validated experimentally by my r ... Full text Cite

Computational hyperspectral unmixing using the AFSSI-C

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 We have previously introduced a high throughput multiplexing computational spectral imaging device. The device measures scalar projections of pseudo-arbitrary spectral filters at each spatial pixel. This paper discusses simulation and initial experimental ... Full text Cite

Introduction

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2016 Full text Cite

Order of Magnitude Signal Gain in Magnetic Sector Mass Spectrometry Via Aperture Coding.

Journal Article Journal of the American Society for Mass Spectrometry · September 2015 Miniaturizing instruments for spectroscopic applications requires the designer to confront a tradeoff between instrument resolution and instrument throughput [and associated signal-to-background-ratio (SBR)]. This work demonstrates a solution to this trade ... Full text Cite

THz photoconductive antenna array based near field imaging

Journal Article International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2013 · August 24, 2015 Full text Cite

Compressive sensing in the EO/IR.

Journal Article Applied optics · March 2015 We investigate the utility of compressive sensing (CS) to electro-optic and infrared (EO/IR) applications. We introduce the field through a discussion of historical antecedents and the development of the modern CS framework. Basic economic arguments (in th ... Full text Cite

Two-dimensional aperture coding for magnetic sector mass spectrometry.

Journal Article Journal of the American Society for Mass Spectrometry · February 2015 In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would ... Full text Cite

Terahertz digital holographic imaging of voids within visibly opaque dielectrics

Journal Article IEEE Transactions on Terahertz Science and Technology · January 1, 2015 Terahertz digital off-axis holography (THzDH) has been demonstrated as a non-destructive tool for imaging voids within visually opaque dielectrics. Using a raster scanning heterodyne detector, the imager captures lensless transmission holograms formed by t ... Full text Open Access Cite

Hyperspectral Unmixing using the AFSSI-C

Conference Optics InfoBase Conference Papers · January 1, 2015 We investigate the use of the Adaptive Feature Specific Spectral Imaging Classifier (AFSSI-C) architecture to perform spectral unmixing. Through simulations using a variety of static coding schemes, we demonstrate that the AFSSI-C outperforms traditional h ... Cite

Adaptive Spectral Imaging Classification

Conference Imaging and Applied Optics 2015 · 2015 Full text Cite

Terahertz emission properties of butterfly-shaped photoconductive antennas based on LT-GaAs and SI-GaAs substrates

Conference International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · November 13, 2014 Photoconductive antennas (PCA) (one of the most commonly used terahertz emitters) have limited performance (e.g. low output power) and as such, do not fully meet the increasing needs of applications. This work attempts to find a route to further improve th ... Full text Cite

Millimeter wave luneburg lens antenna fabricated by polymer jetting rapid prototyping

Conference International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · November 13, 2014 In this paper, the design, fabrication and characterization of a 3D printed Luneburg lens antenna working at Ka and Q band are proposed. Gradient index control of the lens is based on the mixing ratio of air voids and polymer. The effective dielectric cons ... Full text Cite

Terahertz digital holographic imaging of visibly opaque printed dielectrics

Conference International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · November 13, 2014 Terahertz digital off-axis holography has been demonstrated as a non-destructive imaging tool for three-dimensional (3D) printed structures. Digital holographic reconstructions from two structures were used to measure the imager's modulation transfer funct ... Full text Cite

Theoretical and experimental study of a terahertz time-domain spectrometer based on photoconductive antenna

Conference 2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014 · October 16, 2014 We construct a terahertz time-domain spectrometer (THz-TDS) system based on photoconductive antenna (PCA). A 800 nm Ti:sapphire femtosecond laser with 80 MHz repetition rate provides the pump and probe laser pulse, which has a 45 fs pulse width (as short a ... Full text Cite

Experimental validation of the adaptive feature-specific spectral imaging classifier (AFSSI-C)

Conference Frontiers in Optics, FiO 2014 · October 14, 2014 © 2014 Optical Society of America. We present experimental results for the Adaptive Feature-Specific Spectral Imaging Classifier (AFSSI-C) that are in excellent quantitative agreement with simulation. Performance gains >1000x relative to conventional appro ... Cite

Experimental validation of the adaptive feature-specific spectral imaging classifier (AFSSI-C)

Conference Frontiers in Optics, FiO 2014 · October 14, 2014 We present experimental results for the Adaptive Feature-Specific Spectral Imaging Classifier (AFSSI-C) that are in excellent quantitative agreement with simulation. Performance gains >1000x relative to conventional approaches are predicted for expanded sy ... Full text Cite

Comparison of photoconductive antenna performance on LT-GaAs and SI-GaAs substrates

Conference IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) · September 18, 2014 In this work, butterfly shaped photoconductive antennas (PCAs) on low-temperature grown (LT) GaAs and semi-insulating (SI) GaAs substrate as terahertz (THz) emitters are experimentally characterized and compared. Dependences of the THz radiated field on th ... Full text Cite

Compressive mass analysis on quadrupole ion trap systems.

Journal Article Journal of the American Society for Mass Spectrometry · July 2014 Conventionally, quadrupole ion trap mass spectrometers eject ions of different mass-to-charge ratio (m/z) in a sequential fashion by performing a scan of the rf trapping voltage amplitude. Due to the inherent sparsity of most mass spectra, the detector mea ... Full text Cite

Characterization of the AWARE 10 two-gigapixel wide-field-of-view visible imager.

Journal Article Applied optics · May 2014 System requirements for many military electro-optic and IR camera systems reflect the need for both wide-field-of-view situational awareness as well as high-resolution imaging for target identification. In this work we present a new imaging system architec ... Full text Cite

Direct rapid-prototyping fabrication of computer-generated volume holograms in the millimeter-wave and terahertz regime.

Journal Article Optics express · February 2014 Computer-generated volume holograms (CGVHs) are gradient refractive index (GRIN) devices that consist of a superposition of multiple periodic diffraction gratings. Fabrication of these components for the visible range is difficult due to the small length-s ... Full text Cite

3D printed dielectric reflectarrays: Low-cost high-gain antennas at sub-millimeter waves

Journal Article IEEE Transactions on Antennas and Propagation · January 1, 2014 Dielectric reflectarray antennas are proposed as a promising low-loss and low-cost solution for high gain terahertz (THz) antennas. Variable height dielectric elements are used in the reflectarray designs, which allow for the use of low dielectric-constant ... Full text Cite

A 3-D luneburg lens antenna fabricated by polymer jetting rapid prototyping

Journal Article IEEE Transactions on Antennas and Propagation · January 1, 2014 In this work, we designed, built, and tested a low-gain 20 dBi Luneburg Lens antenna using a rapid prototyping machine as a proof of concept demonstrator. The required continuously varying relative permittivity profile was implemented by changing the size ... Full text Cite

Broadband electronically beam scanning structure using Luneburg lens

Journal Article IEEE MTT-S International Microwave Symposium Digest · December 1, 2013 A novel broadband electronically beam scanning structure based on Luneburg lens phased array is investigated in this paper. The radiation elements of the phased array are mounted on the surface of a Luneburg lens. Without amplitude and phase control of the ... Full text Cite

Design, fabrication, and measurement of dielectric reflectarray antennas at 100 GHz

Journal Article International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · December 1, 2013 Dielectric reflectarray antennas are proposed as a possible low-loss solution for high gain THz antennas. A 3-D printing technology is utilized to fabricate the antenna, and numerical and experimental results are presented for a prototype operating at 100 ... Full text Cite

Adaptive feature-specific spectral imaging classifier (AFSSI-C)

Journal Article Proceedings of the International Telemetering Conference · December 1, 2013 The AFSSI-C is a spectral imager that generates spectral classification directly, in fewer measurements than are required by traditional systems that measure the spectral datacube (which is later interpreted to make material classification). By utilizing a ... Cite

High gain dielectric reflectarray antennas for THz applications

Journal Article IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) · December 1, 2013 Dielectric reflectarray antennas are studied in this paper as a possible low-loss and low-cost solution for high gain THz antennas. Variable height dielectric slabs are proposed for the reflectarray elements which allow for the use of low dielectric-consta ... Full text Cite

Calibration of high dimensional compressive sensing systems: A case study in compressive hyperspectral imaging

Journal Article Proceedings of the International Telemetering Conference · December 1, 2013 Compressive Sensing (CS) is a set of techniques that can faithfully acquire a signal from sub- Nyquist measurements, provided the class of signals have certain broadly-applicable prop- erties. Reconstruction (or exploitation) of the signal from these sub-N ... Cite

Electromagnetic crystal (EMXT) based Terahertz horn antenna

Journal Article 2013 7th European Conference on Antennas and Propagation, EuCAP 2013 · August 14, 2013 The design, fabrication and measured performance of an all-dielectric Terahertz (THz) horn antenna based on hollow-core electromagnetic crystal structure is described. Simulation result shows that the antenna works above 100 GHz, with better than 30 dB ret ... Cite

Petapixel photography and the limits of camera information capacity

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · April 10, 2013 The monochromatic single frame pixel count of a camera is limited by diffraction to the space-bandwidth product, roughly the aperture area divided by the square of the wavelength. We have recently shown that it is possible to approach this limit using mult ... Full text Cite

Computational optical sensing and imaging: introduction to feature issue.

Journal Article Applied optics · April 2013 The 2012 Computational Optical Sensing and Imaging (COSI) conference of the Optical Society of America was one of six colocated meetings composing the Imaging and Applied Optics Congress held in Monterey, California, 24-28 June. COSI, together with the Ima ... Full text Cite

Big snapshot stitching with scarce overlap

Journal Article 2013 IEEE High Performance Extreme Computing Conference, HPEC 2013 · January 1, 2013 We address certain properties that arise in gigapixel-scale image stitching for snapshot images captured with a novel micro-camera array system, AWARE-2. This system features a greatly extended field of view and high optical resolution, offering unique sen ... Full text Cite

Color image formation for multiscale gigapixel imaging

Journal Article Optics InfoBase Conference Papers · January 1, 2013 We present the current development of the image formation pipeline for color gigapixel images obtained by the AWARE-10 multiscale camera.We introduce a camera simulator, the modifications to the scalable pipeline, and the challenges for creating seamless c ... Cite

Efficient model-based tonemapping of high dynamic range gigapixel images

Journal Article Optics InfoBase Conference Papers · January 1, 2013 We present a technique to address the tonemapping of high dynamic range (HDR) gigapixel images. The proposed method relies on extracting low-dimensional models from lowresolution proxy images, and can be efficiently implemented in a parallel manner. © OSA ... Cite

Calibration challenges and initial experimental demonstration of an adaptive, feature-specific spectral imaging classifier

Journal Article Optics InfoBase Conference Papers · January 1, 2013 We describe the calibration challenges associated with a computational spectral imaging classifier and present initial experimental results. We also discuss planned system improvements to address these calibration challenges and observed performance issues ... Cite

Efficient model-based tonemapping of high dynamic range gigapixel images

Conference Optics InfoBase Conference Papers · January 1, 2013 We present a technique to address the tonemapping of high dynamic range (HDR) gigapixel images. The proposed method relies on extracting low-dimensional models from lowresolution proxy images, and can be efficiently implemented in a parallel manner. © OSA ... Full text Cite

Calibration challenges and initial experimental demonstration of an adaptive, feature-specific spectral imaging classifier

Conference Optics InfoBase Conference Papers · January 1, 2013 We describe the calibration challenges associated with a computational spectral imaging classifier and present initial experimental results. We also discuss planned system improvements to address these calibration challenges and observed performance issues ... Full text Cite

Color image formation for multiscale gigapixel imaging

Conference Optics InfoBase Conference Papers · January 1, 2013 We present the current development of the image formation pipeline for color gigapixel images obtained by the AWARE-10 multiscale camera.We introduce a camera simulator, the modifications to the scalable pipeline, and the challenges for creating seamless c ... Full text Cite

Terahertz horn antenna based on hollow-core electromagnetic crystal (EMXT) structure

Journal Article IEEE Transactions on Antennas and Propagation · December 17, 2012 An all-dielectric terahertz (THz) horn antenna based on hollow-core electromagnetic crystal structure is designed, fabricated and characterized. Simulation shows that the antenna works above 100 GHz, with better than 30 dB return loss and highly directiona ... Full text Cite

Fabrication of terahertz gradient-index components via 3D rapid prototyping

Journal Article Optics InfoBase Conference Papers · December 1, 2012 New advancements in 3D rapid prototyping have allowed us to explore the development of terahertz gradient-index components. We report on our progress with designing and fabricating terahertz computer generated volume hologram gradient-index components. © 2 ... Cite

A static architecture for compressive target tracking

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 2012 Traditional approaches to persistent surveillance generate prodigious amounts of data, stressing storage, communication, and analysis systems. As such, they are well suited for compressed sensing (CS) concepts. Existing demonstrations of compressive target ... Full text Cite

Novel Broadband Direction of Arrival Estimation Using Luneburg Lens

Journal Article Proceedings of the International Telemetering Conference · December 1, 2012 A broadband passive direction finding system utilizing Luneburg lens has been investigated. With the simulated power level distribution at the detectors mounted on a Luneburg lens, both Cramér-Rao bound (CRB) and the root mean square error (RMS) based on t ... Cite

3D rapid prototyping of terahertz computer-generated volume holograms

Journal Article International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz · December 1, 2012 New 3D rapid prototyping technology has allowed for fast and inexpensive fabrication of terahertz gradient-index components. We report on our progress in the fabrication and testing of terahertz computer-generated volume holograms. © 2012 IEEE. ... Full text Cite

Direction of arrival estimation using Luneburg lens

Journal Article IEEE MTT-S International Microwave Symposium Digest · October 3, 2012 In this paper, a 3-D Luneburg Lens is employed for direction finding application. Using the special property of a Luneburg lens that every point on the surface of the Lens is the focal point of a plane wave incident from the opposite side, a number of dete ... Full text Cite

Development of a scalable image formation pipeline for multiscale gigapixel photography.

Journal Article Optics express · September 2012 We report on the image formation pipeline developed to efficiently form gigapixel-scale imagery generated by the AWARE-2 multiscale camera. The AWARE-2 camera consists of 98 "microcameras" imaging through a shared spherical objective, covering a 120° x 50° ... Full text Cite

Static compressive tracking.

Journal Article Optics express · September 2012 This paper presents the Static Computational Optical Undersampled Tracker (SCOUT), an architecture for compressive motion tracking systems. The architecture uses compressive sensing techniques to track moving targets at significantly higher resolution than ... Full text Cite

Adaptive feature-specific spectral imaging

Conference Proceedings of SPIE - The International Society for Optical Engineering · July 23, 2012 We present an architecture for rapid spectral classification in spectral imaging applications. By making use of knowledge gained in prior measurements, our spectral imaging system is able to design adaptive feature-specific measurement kernels that selecti ... Full text Cite

Multiscale gigapixel photography.

Journal Article Nature · June 2012 Pixel count is the ratio of the solid angle within a camera's field of view to the solid angle covered by a single detector element. Because the size of the smallest resolvable pixel is proportional to aperture diameter and the maximum field of view is sca ... Full text Cite

Challenges in gigapixel multiscale image formation

Journal Article Imaging Systems and Applications, ISA 2012 · January 1, 2012 We present new results from the image formation team on the AWARE Wide-Field project. We will report on new strategies prompted by new challenges encountered in experiments with two prototype AWARE Wide-Field systems. © 2012 OSA. ... Full text Cite

Challenges in gigapixel multiscale image formation

Journal Article Imaging Systems and Applications, ISA 2012 · 2012 Cite

Advances in the design, calibration and use of a static coded aperture compressive tracking and imaging system

Journal Article Computational Optical Sensing and Imaging, COSI 2012 · January 1, 2012 We present our latest results in static compressive tracking and imaging. We have developed a design methodology using the compressed sensing concept of mutual coherence. We also elucidate a modified calibration scheme that boosts compressive imaging capab ... Full text Cite

AFSSI-C: The adaptive feature-specific spectral imaging classifier

Journal Article Computational Optical Sensing and Imaging, COSI 2012 · January 1, 2012 We have developed an architecture for spectral classification in spectral imaging. Adaptive kernels are designed using probabilistically-weighted principal component analysis. Simulation predicts orders-of-magnitude reduction in error rates, and a prototyp ... Full text Cite

Challenges in gigapixel multiscale image formation

Journal Article Imaging Systems and Applications, ISA 2012 · January 1, 2012 We present new results from the image formation team on the AWARE Wide-Field project. We will report on new strategies prompted by new challenges encountered in experiments with two prototype AWARE Wide-Field systems. © 2012 OSA. ... Cite

Optical testing of the AWARE wide field 2-gigapixel multiscale camera

Journal Article Optics InfoBase Conference Papers · December 1, 2011 Testing a 2-Gigapixel 8 arcsec IFOV, 120° FOV camera requires integration of precision mechanical automation, optical instrumentation, image diagnostics, electronics and networking hardware. We detail the ongoing AWARE Wide Field Camera efforts. © 2011 OSA ... Cite

Image formation in multiscale optical systems

Journal Article Optics InfoBase Conference Papers · December 1, 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Cite

Experimental demonstration of compressive target tracking

Journal Article Optics InfoBase Conference Papers · December 1, 2011 We present an experimental demonstration of compressive target tracking-detection of mover locations with a spatial resolution finer than that provided by the detector pixel dimensions. The tracking performance is evaluated with a customized metric. © 2011 ... Cite

Fabrication and testing of computer-generated volume holograms in the terahertz

Journal Article Optics InfoBase Conference Papers · December 1, 2011 Advances in rapid prototyping technology have allowed for successful fabrication of terahertz computer-generated volume holograms. We report on our progress in the design, fabrication, and measurement of our first successful holograms. FIO/ LS Technical Di ... Cite

Information-optimal adaptive feature-specific spectroscopy for rapid chemical classification

Journal Article Optics InfoBase Conference Papers · December 1, 2011 An information-optimal version of Adaptive Feature-Specific Spectrometry (AFSS) is presented. The system achieves dramatically shorter time-to-classification than traditional architectures in low SNR scenarios. © 2011 OSA. ... Cite

Adaptive, feature-specific spectral imaging classifier

Journal Article Optics InfoBase Conference Papers · December 1, 2011 We describe our design for an adaptive, feature-specific spectral imaging classifier. The system utilizes adaptive spectral codes to spectrally-classify multiple spectral locations in parallel © 2011 OSA. ... Cite

Terahertz all-dielectric EMXT waveguide to planar microstrip transition structure

Journal Article IRMMW-THz 2011 - 36th International Conference on Infrared, Millimeter, and Terahertz Waves · December 1, 2011 Terahertz all-dielectric Electromagnetic Crystal (EMXT) waveguide to planar microstrip line transition structures are designed, simulated and fabricated. The design is similar to the ridge coupling structure used in metallic waveguide to microstrip transit ... Full text Cite

An X-band Luneburg lens antenna fabricated by rapid prototyping technology

Journal Article IEEE MTT-S International Microwave Symposium Digest · September 7, 2011 In this paper, a 3-D Luneburg Lens has been designed, fabricated and characterized. Refractive index control of the lens is based on the mixing ratio of air voids and a polymer. The 12 cm (4λ0 at 10 GHz) diameter lens is designed to work at X-band. The eff ... Full text Cite

Image formation challenges in the MOSAIC platform

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · July 21, 2011 The DARPA MOSAIC program applies multiscale optical design (shared objective lens and parallel array of microcameras) to the acquisition of high pixel count images. Interestingly, these images present as many challenges as opportunities. The imagery is acq ... Full text Cite

Electromagnetic crystal (EMXT)-based THz components

Conference Proceedings of SPIE - The International Society for Optical Engineering · June 9, 2011 Various all-dielectric electromagnetic crystal (EMXT) based THz components, including filter/reflector, waveguide, antenna, and transition structure to planar circuits are proposed and simulated. Several of them have been fabricated via a THz rapid prototy ... Full text Cite

Electromagnetic crystal (EMXT) based THz waveguide and horn antenna fabricated by polymer jetting quick prototyping

Journal Article Final Program and Book of Abstracts - iWAT 2011: 2011 IEEE International Workshop on Antenna Technology: Small Antennas, Novel Structures and Innovative Metamaterials · June 7, 2011 All dielectric THz waveguide and horn antenna designed utilizing hollow core electromagnetic crystal (EMXT) structures are presented here. Very low loss (0.03 dB / mm) waveguide above 100 GHz has been achieved. Flared horn antenna based on this waveguide h ... Full text Cite

Electromagnetic crystal based components for terahertz characterization and applications

Journal Article 2011 IEEE 11th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, SiRF 2011 - Digest of Papers · March 25, 2011 Various electromagnetic crystal (EMXT) based THz components, including filter/reflector, waveguide, antenna, and transition structure to planar circuits are proposed and simulated. Several of them have been fabricated via a THz rapid prototyping technique, ... Full text Cite

Adaptive feature specific spectroscopy for rapid chemical identification.

Journal Article Optics express · February 2011 Spectroscopic chemical classification based on adaptive, feature-specific measurements has been implemented and demonstrated to provide significant performance gain over traditional systems. The measurement scheme and the decision model are discussed. A pr ... Full text Cite

Terahertz electromagnetic crystal waveguide fabricated by polymer jetting rapid prototyping.

Journal Article Optics express · February 2011 An all-dielectric THz waveguide has been designed, fabricated and characterized. The design is based on a hollow-core electromagnetic crystal waveguide, and the fabrication is implemented via polymer-jetting rapid prototyping. Measurements of the waveguide ... Full text Cite

Image formation in multiscale optical systems

Journal Article Optics InfoBase Conference Papers · January 1, 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Full text Cite

Information-optimal adaptive spectral classification imaging

Journal Article Optics InfoBase Conference Papers · January 1, 2011 We propose a notional optical architecture for information-optimal, adaptive spectral classification at multiple spatial locations without acquisition of the spectral datacube. We will report on our simulation, design, and experimental progress. © 2011 OSA ... Full text Cite

Image formation in multiscale optical systems

Journal Article Optics InfoBase Conference Papers · 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Cite

Image formation in multiscale optical systems

Conference Optics InfoBase Conference Papers · January 1, 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Cite

Computer-generated volume holograms in the THz

Journal Article Optics InfoBase Conference Papers · December 1, 2010 Recent advances in rapid prototyping provide the promise of direct, rapid fabrication of volumetric optical components in the terahertz. We are investigating use of this new technology for fabrication of a Bragg-selective computer-generated volume hologram ... Cite

Computer-generated volume holograms in the THz

Journal Article Optics InfoBase Conference Papers · December 1, 2010 Recent advances in rapid prototyping provide the promise of direct, rapid fabrication of volumetric optical components in the terahertz. We are investigating use of this new technology for fabrication of a Bragg-selective computer-generated volume hologram ... Cite

Experimental demonstration of adaptive feature-specific spectroscopy

Journal Article Optics InfoBase Conference Papers · December 1, 2010 Experimental validation of Adaptive Feature-Specific Spectroscopy (AFSS) is presented. The system achieves dramatically-shorter time-to-classification times than traditional architectures in low SNR scenarios. © 2010 OSA /FiO/LS 2010. ... Cite

Static architecture for compressive motion detection in persistent, pervasive surveillance applications

Journal Article Optics InfoBase Conference Papers · December 1, 2010 High-resolution, wide-field-of-view airborne imaging produces large optical systems and data streams. Significant simplification is possible if motion detection, rather than full imaging, is the goal. We consider a static, compressive-sensing architecture ... Cite

Terahertz electromagnetic crystal (EMXT) based waveguide and horn antenna

Conference IRMMW-THz 2010 - 35th International Conference on Infrared, Millimeter, and Terahertz Waves, Conference Guide · November 30, 2010 All-dielectric Terahertz waveguides based on hollow-core EMXT fiber are fabricated via THz rapid prototyping using polymer jetting technique. Several waveguides of identical cross-section and differing lengths are characterized by THz time-domain spectrosc ... Full text Cite

Hollow-core electromagnetic band gap (EBG) waveguide fabricated by rapid prototyping for low-loss terahertz guiding

Conference IEEE MTT-S International Microwave Symposium Digest · October 15, 2010 An all-dielectric THz waveguide has been designed, fabricated and characterized. The design is based on electromagnetic band gap (EBG) structures, and the fabrication is implemented with polymer-jetting rapid prototyping method. Measurement results show go ... Full text Cite

Investigation of several terahertz electromagnetic band gap structures

Conference Microwave and Optical Technology Letters · March 1, 2010 Several THz electromagnetic band gap (EBG) structures are investigated and demonstrated. Various design, fabrication, and characterization methods and techniques are utilized and compared. These THz EBG structures may enable future high performance EBG bas ... Full text Cite

Compressive measurements for target tracking

Journal Article Optics InfoBase Conference Papers · January 1, 2010 We present an imaging system for target tracking with compressive measurements for large area persistent surveillance. Multiplexed sensing with a mask-based optical system and signal retrieval from underdetermined measurements using l-1 minimization are ex ... Full text Cite

Systematic design study of an all-optical delay line based on Brillouin scattering enhanced cascade coupled ring resonators

Journal Article Journal of Optics · January 1, 2010 We present a technique to improve the slow-light performance of a side-coupled integrated spaced sequence of resonators (SCISSOR) combined with a stimulated Brillouin scattering (SBS) gain medium in optical fibers. We evaluate device performance of SCISSOR ... Full text Cite

Hollow-core Electromagnetic Band Gap (EBG) Waveguide Fabricated by Rapid Prototyping for Low-loss Terahertz Guiding

Conference 2010 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST (MTT) · 2010 Cite

All-dielectric low-loss Terahertz waveguide fabricated by rapid prototyping

Conference 34th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2009 · December 31, 2009 An all-dielectric Terahertz waveguide is designed based on hollow-core photonic crystal fiber. Simulation shows a waveguide transmission loss as low as 0.019 dB/mm near 140 GHz with a working bandwidth of approximately 18 GHz. Several waveguides of identic ... Full text Cite

Adaptive feature-specific spectroscopy

Journal Article Optics InfoBase Conference Papers · December 1, 2009 We introduce the Adaptive Feature-Specific Spectrometer (AFSS), a chemical-detection methodology that uses an adaptively reconfigured set of signal projections to drastically shorten time-to-identification in low-SNR situations. © 2009 Optical Society of A ... Cite

Compressive measurement for target tracking in persistent, pervasive surveillance applications

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · December 1, 2009 Motion tracking in persistent surveillance applications enters an interesting regime when the movers are of a size on the order of the image resolution elements or smaller. In this case, for reasonable scenes, information about the movers is a natively spa ... Full text Cite

Novel Applications of Rapid Prototyping in Gamma-ray and X-ray Imaging.

Journal Article IEEE Nuclear Science Symposium conference record. Nuclear Science Symposium · October 2009 Advances in 3D rapid-prototyping printers, 3D modeling software, and casting techniques allow for the fabrication of cost-effective, custom components in gamma-ray and x-ray imaging systems. Applications extend to new fabrication methods for custom collima ... Full text Cite

Rapid prototyping for fabrication of GHz-THz bandgap structures

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · September 8, 2009 Recent advances in rapid prototyping technologies have resulted in build-resolutions that are now on the scales required for direct fabrication of photonic structures in the gigahertz (GHz) and terahertz (THz) regimes. To demonstrate this capability, we ha ... Full text Cite

Adaptive spectroscopy for rapid chemical identification

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · September 7, 2009 Spectroscopic chemical identification is fundamentally a classification task where sensor measurements are compared to a library of known compounds with the hope of determining an unambiguous match. When the measurement signal-to-noise ratio (SNR) is very ... Full text Cite

Adaptive dynamic range matching for spectroscopic measurements.

Journal Article Applied optics · April 2009 We describe the design and development of an adaptive spectrometer that actively manages dynamic range mismatch between source signals and the spectrometer's detector. The introduction of an inexpensive digital micromirror array yields performance improvem ... Full text Cite

Fabrication of GHz/THz volumetric optics via rapid prototyping

Journal Article Optics InfoBase Conference Papers · January 1, 2009 Rapid prototyping technology is now capable of high-resolution fabrication suitable for producing volumetric optics in the GHz/THz range. We will report on our successful fabrication of photonic crystal structures and discuss other components under study. ... Full text Cite

Rapid and inexpensive fabrication of terahertz electromagnetic bandgap structures.

Journal Article Optics express · October 2008 Modern rapid prototyping technologies are now capable of build resolutions that allow direct fabrication of photonic structures in the GHz and THz frequency regimes. To demonstrate this, we have fabricated several structures with 3D electromagnetic bandgap ... Full text Cite

High-throughput, multiplexed pushbroom hyperspectral microscopy.

Journal Article Optics express · July 2008 We describe a high-throughput hyperspectral microscope. The system replaces the slit of conventional pushbroom spectral imagers with a static coded aperture mask. We present the theoretical underpinnings of the aperture coded spectral engine and describe t ... Full text Cite

Adaptive spectroscopy: Towards adaptive spectral imaging

Conference Proceedings of SPIE - The International Society for Optical Engineering · May 20, 2008 Spectral imaging is an emerging tool for defense and security applications because it provides compositional information about the objects in a scene. The underlying task-measuring a 3-D dataset using a 2-D detector array-is challenging, and straightforwar ... Full text Cite

Single-shot compressive spectral imaging with a dual-disperser architecture.

Journal Article Optics express · October 2007 This paper describes a single-shot spectral imaging approach based on the concept of compressive sensing. The primary features of the system design are two dispersive elements, arranged in opposition and surrounding a binary-valued aperture code. In contra ... Full text Cite

Multiscale reconstruction for computational spectral imaging

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · August 31, 2007 In this work we develop a spectral imaging system and associated reconstruction methods that have been designed to exploit the theory of compressive sensing. Recent work in this emerging field indicates that when the signal of interest is very sparse (i.e. ... Full text Cite

Performance comparison of aperture codes for multimodal, multiplex spectroscopy.

Journal Article Applied optics · August 2007 We experimentally evaluate diverse static independent column codes in a coded aperture spectrometer. The performance of each code is evaluated based on the signal-to-noise ratio (SNR), defined as the peak value in the spectrum to the standard deviation of ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer.

Journal Article Optics express · April 2007 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array at the detector plane. The two-dimensional aperture code is based on a row-doubled Hadamard mask with transmissive and opaque openings. T ... Full text Cite

Multiple order coded aperture spectrometer.

Journal Article Optics express · April 2007 We introduce a multiple order coded aperture (MOCA) spectrometer. The MOCA is a system that uses a multiplex hologram and a coded aperture to increase the spectral range and throughput of the system over conventional spectrometers while maintaining spectra ... Full text Cite

A snap-shot dual-disperser imager for compressive hyperspectral imaging

Journal Article Optics InfoBase Conference Papers · January 1, 2007 We demonstrate a single-shot, dual-disperser spectral imaging system using coded apertures to perform compressive imaging. We also describe associated multiscale reconstruction algorithms to retrieve hyperspectral data from single-shot image. We show simul ... Full text Cite

Hyperspectral imager based on coded-aperture spectroscopy

Journal Article Optics InfoBase Conference Papers · January 1, 2007 A hyperspectral imager based on coded-aperture spectroscopy has excellently generated 3-D data cube that provides 2-D images of a sample with high selectivity of wavelength as well as spectrum with meaningful spectral features. © 2007 Optical Society of Am ... Full text Cite

Optical designs for compressive single shot spectral imaging

Journal Article Optics InfoBase Conference Papers · January 1, 2007 Static mask coded aperture spectral imaging enables compact, programmable coding for single shot measurements. We review recent demonstrations of spectral imaging systems in the DISP lab and describes trade-offs in dispersion and coding system design. © 20 ... Full text Cite

Adaptive spectroscopy

Journal Article Optics InfoBase Conference Papers · January 1, 2007 We report on our theoretical and experimental investigations of adaptive spectroscopy-the introduction of active filters into spectrometer design. Simulations indicate these systems can achieve sensor performance beyond that of traditional approaches. © 20 ... Full text Cite

Quantitative dynamic range management techniques for spectroscopic detection and estimation

Journal Article Optics InfoBase Conference Papers · January 1, 2007 Introduction of active filters into spectrometer design results in flexible systems that are insensitive to source/detector dynamic range mismatch, thereby allowing detection of spectral features that were previously below the detection limit. © 2007 Optic ... Cite

Compressive spectral imaging and multiscale reconstruction methods

Conference Optics InfoBase Conference Papers · January 1, 2007 In this work we develop a single-shot, dual-disperser spectral imaging system and associated multiscale photon-limited multispectral reconstruction methods that have been designed to exploit the emerging theory of compressive sensing. © 2007 Optical Societ ... Cite

Compressive spectral imaging and multiscale reconstruction methods

Conference Optics InfoBase Conference Papers · January 1, 2007 In this work we develop a single-shot, dual-disperser spectral imaging system and associated multiscale photon-limited multispectral reconstruction methods that have been designed to exploit the emerging theory of compressive sensing. © 2007 Optical Societ ... Full text Cite

Quantitative dynamic range management techniques for spectroscopic detection and estimation

Conference Optics InfoBase Conference Papers · January 1, 2007 Introduction of active filters into spectrometer design results in flexible systems that are insensitive to source/detector dynamic range mismatch, thereby allowing detection of spectral features that were previously below the detection limit. © 2007 Optic ... Full text Cite

Dispersion multiplexing with broadband filtering for miniature spectrometers.

Journal Article Applied optics · January 2007 We replace the traditional grating used in a dispersive spectrometer with a multiplex holographic grating to increase the spectral range sensed by the instrument. The multiplexed grating allows us to measure three different, overlapping spectral bands on a ... Full text Cite

Compressive imaging spectrometers using coded apertures

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · August 23, 2006 A spectral imager provides a 3-D data cube in which the spatial information (2-D) of the image is comple-mented by spectral information (1-D) about each spatial location. Typically, these systems are operated in a fully-determined (or overdetermined) manne ... Full text Cite

Multimodal multiplex Raman spectroscopy optimized for in vivo chemometrics

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · June 29, 2006 We have designed and constructed a multimodal multiplex Raman spectrometer which uses multi-wavelength excitation to better detect signals in the presence of fluorescence by taking advantage of the shift-variance of the Raman signal with respect to excitat ... Full text Cite

Integrated sensing and processing of Raman spectra for in vivo BAC measurement

Conference ALCOHOLISM-CLINICAL AND EXPERIMENTAL RESEARCH · June 1, 2006 Link to item Cite

High-throughput hyperspectral microscopy

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · May 8, 2006 A hyperspectral imager provides a 3-D data cube in which the spatial information (2-D) of the image is complemented by spectral information (1-D) about each spatial location. A static, high-throughput spectrometer design previously developed by our group c ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. © 2006 Optical Society of Ame ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. © 2006 Optical Society of Ame ... Cite

Multiple order coded aperture (MOCA) spectrometer

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We introduce a Multiple Order Coded Aperture (MOCA) spectrometer that uses a crossdispersive hologram and a coded aperture to achieve improved spectral range over traditional dispersive spectrometers at comparable resolution. © 2006 OSA. ... Full text Cite

Pushbroom hyperspectral imaging with a coded aperture

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We describe a hyperspectral camera which operates by translating a scene across the entrance of a coded aperture spectrometer. This applies a sequence of unique codes to the image, allowing full reconstruction of the datacube. © 2006 Optical Society of Ame ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. © 2006 Optical Society of Ame ... Cite

Evaluation of aperture codes for high throughput spectroscopy

Journal Article Optics InfoBase Conference Papers · January 1, 2006 A coded aperture spectrometer maintains the spectral resolution of a traditional slit spectrometer while dramatically increasing the throughput. Here we evaluate the performance of different aperture codes for spectroscopy of weak, incoherent sources. © 20 ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. © 2006 Optical Society of Ame ... Cite

Dual-disperser design for single-shot computational spectral imaging

Journal Article Optics InfoBase Conference Papers · January 1, 2006 We describe a dual-disperser approach to computational spectral imaging. This approach enables flexible code design and avoids problems present in single-disperser systems. We will report on a prototype single-shot spectral imager based on these ideas. © 2 ... Full text Cite

Longwave Infrared (LWIR) Coded Aperture Dispersive Spectrometer

Conference Optics InfoBase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. ... Cite

Coded aperture Raman spectroscopy for quantitative measurements of ethanol in a tissue phantom

Journal Article Applied Spectroscopy · 2006 Coded aperture spectroscopy allows for sources of large etendue to be efficiently coupled into dispersive spectrometers by replacing the traditional input slit with a patterned mask. We describe a coded aperture spectrometer optimized for Raman spectroscop ... Full text Link to item Cite

Compressive sampling strategies for integrated microspectrometers

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · 2006 We consider compressive sensing in the context of optical spectroscopy. With compressive sensing, the ratio between the number of measurements and the number of estimated values is less than one, without compromising the fidelity in estimation. A compressi ... Full text Link to item Cite

Static two-dimensional aperture coding for multimodal, multiplex spectroscopy

Journal Article Applied Optics · 2006 We propose a new class of aperture-coded spectrometer that is optimized for the spectral characterization of diffuse sources. The instrument achieves high throughput and high spectral resolution by replacing the slit of conventional dispersive spectrometer ... Full text Link to item Cite

Multimodal, multiplex, Raman spectroscopy of alcohol in diffuse, fluorescent media

Journal Article Optics InfoBase Conference Papers · January 1, 2005 Optical diagnostics in biological materials are hindered by fluorescence and scattering. We have developed a multimodal, multiplex, coded-aperture Raman spectrometer to detect alcohol in a lipid tissue phantom solution. ©2005 Optical Society of America. ... Cite

Tomographic hyperspectral imaging without a missing-cone

Journal Article Optics InfoBase Conference Papers · January 1, 2005 We describe a hyperspectral imager combining coded aperture spectroscopy and tomographic spatial reconstruction. The throughput of the system is improved compared to scanning techniques while avoiding the missing-cone problem common to many spectral tomogr ... Full text Cite

Multimodal, multiplex Raman spectrometer for weak, incoherent sources

Journal Article Optics InfoBase Conference Papers · January 1, 2005 Raman spectroscopy in bio-materials is complicated by fluorescence and scattering. We have developed a multimodal, multiplex spectrometer that overcomes these difficulties. We are currently constructing a second generation prototype for in-vivo Raman spect ... Cite

Multiplex design for high-performance microspectrometers

Journal Article Optics InfoBase Conference Papers · January 1, 2005 The volume of spectrometers can be drastically reduced through the use of multiplex measurement. Reductions of 3-5 orders of magnitude are possible. This has the potential to drastically effect manufacturing and deployment costs. ©2005 Optical Society of A ... Cite

Multimodal, multiplex Raman spectrometer for weak, incoherent sources

Conference Optics InfoBase Conference Papers · January 1, 2005 Raman spectroscopy in bio-materials is complicated by fluorescence and scattering. We have developed a multimodal, multiplex spectrometer that overcomes these difficulties. We are currently constructing a second generation prototype for in-vivo Raman spect ... Full text Cite

Multiplex design for high-performance microspectrometers

Conference Optics InfoBase Conference Papers · January 1, 2005 The volume of spectrometers can be drastically reduced through the use of multiplex measurement. Reductions of 3-5 orders of magnitude are possible. This has the potential to drastically effect manufacturing and deployment costs. ©2005 Optical Society of A ... Full text Cite

Standoff raman spectroscopy system for remote chemical detection

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · 2005 We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operationa ... Full text Link to item Cite

Multimodal optical spectrometers for remote chemical detection

Journal Article Proceedings of SPIE - The International Society for Optical Engineering · 2005 We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operationa ... Full text Link to item Cite

Multimodal, multiplex, Raman spectroscopy of alcohol in diffuse, fluorescent media

Journal Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · 2005 Optical diagnostics in biological materials are hindered by fluorescence and scattering. We have developed a multimodal, multiplex, coded-aperture Raman spectrometer to detect alcohol in a lipid tissue phantom solution. © 2005 SPIE and OSA. ... Cite

Coded-aperture, multi-wavelength Raman spectroscopy for ethanol detection in biological samples

Conference Proceedings of the 8th Joint Conference on Information Sciences, Vols 1-3 · January 1, 2005 Link to item Cite

Measurement-efficient optical wavemeters.

Journal Article Optics express · December 2004 We describe a method for efficiently determining the wavelength of a monochromatic source and provide an experimental proof-of-concept. The photomeasurement efficiency for a wavemeter can be written as eta(N,q) = (1 + logqN)/m, where N is the number of spe ... Full text Cite

Evidence for superfluidity in a resonantly interacting Fermi gas.

Journal Article Physical review letters · April 2004 We observe collective oscillations of a trapped, degenerate Fermi gas of 6Li atoms at a magnetic field just above a Feshbach resonance, where the two-body physics does not support a bound state. The gas exhibits a radial breathing mode at a frequency of 28 ... Full text Cite

Static, multimodal, multiplex spectrometer design for weak, incoherent sources

Conference Optics InfoBase Conference Papers · January 1, 2004 We present a flexible design for a static, multimodal, multiplex spectrometer which is optimized for the weak incoherent sources that are common in biomedical applications. Simultaneous high throughput and resolution are achieved in a single-shot measureme ... Cite

Multimodal, multiplex Raman spectrometry for detection of ethanol in blood and tissue

Conference Optics InfoBase Conference Papers · January 1, 2004 We investigate the application of static, multimodal, multiplex spectrometers to the detection of the Raman spectrum of ethanol in blood and tissue. These spectrometers are optimized for use with weak, incoherent sources, and enable relatively high sensiti ... Cite

Optically Trapped Fermi Gases

Journal Article American Scientist · 2004 Full text Cite

Optically Trapped Fermi Gases

Journal Article American Scientist · 2004 Full text Cite

Stability of a strongly-attractive, two-component Fermi gas

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · December 1, 2003 Using a simple model, we show that a strongly-attractive, two-component Fermi gas of atoms should be mechanically stable as a consequence of unitarity. We demonstrate this stability experimentally in a degenerate gas of 6Li atoms. ©2000 Optical Society of ... Cite

Observation of hydrodynamic expansion of a strongly-interacting Fermi gas: Signature of superfluidity?

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · December 1, 2003 We observe dramatic anisotropic expansion of a strongly-interacting Fermi gas upon release from an optical trap. The observed hydrodynamic behavior is a possible first signature of the onset of a new type of high-temperature superfluidity. ©2000 Optical So ... Cite

Measurement of the mean-field interaction in a strongly-interacting Fermi gas

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · December 1, 2003 We release a strongly-interacting, two-component Fermi gas from an optical trap. From the release energy, we determine an important, universal many-body parameter: the ratio of the mean-field energy to the local Fermi energy. ©2000 Optical Society of Ameri ... Cite

Stability of a strongly-attractive, two-component Fermi gas

Conference Optics InfoBase Conference Papers · January 1, 2003 Using a simple model, we show that a strongly-attractive, two-component Fermi gas of atoms should be mechanically stable as a consequence of unitarity. We demonstrate this stability experimentally in a degenerate gas of 6Li atoms. ... Cite

Measurement of the mean-field interaction in a strongly-interacting Fermi gas

Conference Optics InfoBase Conference Papers · January 1, 2003 We release a strongly-interacting, two-component Fermi gas from an optical trap. From the release energy, we determine an important, universal many-body parameter: the ratio of the mean-field energy to the local Fermi energy. ... Cite

Observation of hydrodynamic expansion of a strongly-interacting Fermi gas: Signature of superfluidity?

Conference Optics InfoBase Conference Papers · January 1, 2003 We observe dramatic anisotropic expansion of a strongly-interacting Fermi gas upon release from an optical trap. The observed hydrodynamic behavior is a possible first signature of the onset of a new type of high-temperature superfluidity. ... Cite

Mechanical stability of a strongly interacting Fermi gas of atoms

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2003 A strongly attractive, two-component Fermi gas of atoms exhibits universal behavior and should be mechanically stable as a consequence of the quantum-mechanical requirement of unitarity. This requirement limits the maximum attractive force to a value small ... Full text Cite

Unitarity-limited elastic collision rate in a harmonically trapped Fermi gas

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2003 We derive the elastic collision rate for a harmonically trapped Fermi gas in the extreme unitarity limit where the s-wave scattering cross section is [Formula Presented] with [Formula Presented] the relative momentum. The collision rate is given in the for ... Full text Cite

Dynamics of a highly-degenerate, strongly-interacting Fermi gas of atoms

Journal Article Journal of Low Temperature Physics · 2003 Cite

Observation of a strongly interacting degenerate Fermi gas of atoms.

Journal Article Science (New York, N.Y.) · December 2002 We report on the observation of a highly degenerate, strongly interacting Fermi gas of atoms. Fermionic lithium-6 atoms in an optical trap are evaporatively cooled to degeneracy using a magnetic field to induce strong, resonant interactions. Upon abruptly ... Full text Cite

All-optical production of a degenerate Fermi gas.

Journal Article Physical review letters · March 2002 We achieve degeneracy in a mixture of the two lowest hyperfine states of 6Li by direct evaporation in a CO2 laser trap, yielding the first all optically produced degenerate Fermi gas. More than 10(5) atoms are confined at temperatures below 4 microK at ful ... Full text Cite

Measurement of the zero crossing in a Feshbach resonance of fermionic [Formula Presented]

Journal Article Physical Review A - Atomic, Molecular, and Optical Physics · January 1, 2002 We measure a zero crossing in the scattering length of a mixture of the two lowest hyperfine states of [Formula Presented] To locate the zero crossing, we monitor the decrease in temperature and atom number arising from evaporation in a [Formula Presented] ... Full text Cite

Preparation of a degenerate, two-component fermi gas by evaporation in a single beam optical trap

Journal Article Conference on Quantum Electronics and Laser Science (QELS) - Technical Digest Series · January 1, 2002 Degenerate two-component Fermi gases offer possibilities for precision studies of pairing interactions in systems for which the density, temperature, and interaction strength are widely available. Of particular interest are the two-component mixtures of 40 ... Cite

Optically-trapped Fermi gas

Conference Technical Digest - Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, QELS 2001 · January 1, 2001 Summary form only given. Cold, dense gases of fermions offer exciting new opportunities for fundamental studies of quantum degeneracy, collective behavior, and superfluidity. Fermionic 6Li has been the subject of numerous theoretical treatments. This is du ... Full text Cite

Modeling the evaporative cooling of fermionic atoms in an optical trap

Conference Technical Digest - Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, QELS 2001 · January 1, 2001 Summary form only given. Evaporative cooling of atoms in an optical trap has recently received renewed attention as a means for obtaining degeneracy in an optically trapped bosonic Cs vapor as well as a fermionic Li gas. We have developed a new model descr ... Full text Cite

Loading Dynamics of CO2 Laser Traps

Journal Article Phys. Rev. A · 2001 Cite

Loading dynamics of CO2 laser traps

Journal Article Physical Review A. Atomic, Molecular, and Optical Physics · January 1, 2001 The spatial loading dynamics of a carbon dioxide (CO2) laser trap and the equilibrium number of trapped atoms are described using Fokker-Planck model. The absorption of the magneto-optical trap (MOT) beams in the high density region of the (CO2) laser trap ... Cite

Stable, strongly attractive, two-state mixture of lithium fermions in an optical trap

Journal Article Physical review letters · September 2000 We use an all-optical trap to confine a strongly attractive two-state mixture of lithium fermions. By measuring the rate of evaporation from the trap, we determine the effective elastic scattering cross section 4pia(2) to show that the magnitude of the sca ... Full text Cite

Ultrastable CO2laser trapping of lithium fermions

Journal Article Physical Review Letters · January 1, 1999 We demonstrate an ultrastable CO2laser trap that provides tight confinement of neutral atoms with negligible optical scattering and minimal laser-noise-induced heating. Using this method, fermionic6Li atoms are stored in a 0.4 mK deep well with a 1/e trap ... Full text Cite

Dynamics of Noise-Induced Heating in Atom Traps

Journal Article Phys. Rev. A · 1998 Cite