Dr. Neelam Gupta Profile

Dr. Neelam Gupta

Physicist

SPIE Involvement:

Author

Publications (63)

SPIE Journal Paper | 19 March 2023 Open Access

Improving transmittance of long-wave infrared guided-mode resonant filters

Neelam Gupta, Junyeob Song

OE, Vol. 62, Issue 03, 035102, (March 2023) https://doi.org/10.1117/12.10.1117/1.OE.62.3.035102

KEYWORDS: Tunable filters, Transmittance, Optical filters, Long wavelength infrared, Polarization, Zinc selenide, Quantum cascade lasers, FT-IR spectroscopy, Dielectric polarization, Germanium

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Proceedings Article | 5 March 2022 Poster + Presentation + Paper

Tunable guided-mode resonance filters operating in the longwave infrared spectral region

N. Gupta, R. Magnusson, K. Lee, Y. Ko, J. Song

Proceedings Volume 12004, 120040P (2022) https://doi.org/10.1117/12.2604384

KEYWORDS: Optical filters, Polarization, Germanium, Long wavelength infrared, Dielectric polarization, Transmittance, Quantum cascade lasers, Reactive ion etching, Infrared radiation, Dielectrics

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Proceedings Article | 12 April 2021 Presentation + Paper

Longwave infrared tunable notch filters

Neelam Gupta, Robert Magnusson, Mark Lucente

Proceedings Volume 11723, 117230B (2021) https://doi.org/10.1117/12.2596261

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Proceedings Article | 12 April 2021 Paper

Towards high-performance resonant filter for the long-wave infrared band: fabrication and characterization of notch filters based on the guided-mode resonance effect

Junyeob Song, Neelam Gupta

Proceedings Volume 11723, 117230J (2021) https://doi.org/10.1117/12.2596294

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Proceedings Article | 5 March 2021 Presentation + Paper

Perfect reflection by dielectric subwavelength particle arrays: causes, implications, and technology

Robert Magnusson, Yeong Hwan Ko, Kyu Jin Lee, Pawarat Bootpakdeetam, Nasrin Razmjooei, Fairooz Abdullah Simlan, Ren-Jie Chen, Joseph Buchanan-Vega, Daniel Carney, Hafez Hemmati, Neelam Gupta

Proceedings Volume 11689, 1168912 (2021) https://doi.org/10.1117/12.2578953

KEYWORDS: Dielectrics, Nanoparticles, Waveguide modes, Reflectors, Polarizers, Physics, Photonic crystals, Nanostructuring, Nanostructures, Modulation

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Proceedings Article | 5 March 2021 Presentation + Paper

Progress in tunable longwave infrared notch filters

N. Gupta, R. Magnusson, Y. Ko, K. Lee, J. Song

Proceedings Volume 11694, 1169414 (2021) https://doi.org/10.1117/12.2582552

KEYWORDS: Long wavelength infrared, Linear filtering, Infrared radiation, Optical filters, Refractive index, Quantum cascade lasers, Germanium, FT-IR spectroscopy, Dielectrics, Dielectric polarization

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Proceedings Article | 26 February 2020 Paper

Development of tunable longwave infrared filters based on guided-mode resonance

Neelam Gupta, Mark Mirotznik, Robert Magnusson

Proceedings Volume 11284, 112840N (2020) https://doi.org/10.1117/12.2545136

KEYWORDS: Optical filters, Germanium, Quantum cascade lasers, Dielectric filters, Waveguides, FT-IR spectroscopy, Collimation, Tunable filters, Long wavelength infrared

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Proceedings Article | 13 May 2019 Paper

Development of tunable longwave infrared metamaterial notch filters

Neelam Gupta, Mark Mirotznik

Proceedings Volume 10980, 109800R (2019) https://doi.org/10.1117/12.2523547

KEYWORDS: Optical filters, Transmittance, Long wavelength infrared, Polarization, Dielectric filters, Germanium, FT-IR spectroscopy, Tunable filters, Dielectrics

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SPIE Journal Paper | 6 December 2018 Open Access

Performance characterization of tunable longwave infrared notch filters using quantum cascade lasers

Neelam Gupta, Mark S. Mirotznik

OE, Vol. 57, Issue 12, 127101, (December 2018) https://doi.org/10.1117/12.10.1117/1.OE.57.12.127101

KEYWORDS: Optical filters, Quantum cascade lasers, Long wavelength infrared, Germanium, Linear filtering, Tunable filters, Infrared radiation, Antireflective coatings, Dielectric filters, Dielectrics

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Proceedings Article | 13 November 2018 Presentation + Paper

Anomalous thermal expansion of mercurous halides

Priyanthi Amarasinghe, Joo-Soo Kim, Feng Jin, Sudhir Trivedi, Syed Qadri, Jerry Feng, Jolanta Soos, Mark Diestler, Neelam Gupta, Janet Jensen, James Jensen

Proceedings Volume 10766, 107660M (2018) https://doi.org/10.1117/12.2323375

KEYWORDS: Mercury, Chemical species

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Proceedings Article | 21 February 2018 Paper

Characterization of tunable longwave infrared filters using quantum cascade lasers

Neelam Gupta, Mark Mirotznik

Proceedings Volume 10541, 105411B (2018) https://doi.org/10.1117/12.2287498

KEYWORDS: Optical filters, Quantum cascade lasers, Germanium, Dielectric filters, Tunable filters, Dielectrics, Long wavelength infrared, Reflectivity, Antireflective coatings, Polarization

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Proceedings Article | 30 August 2017 Paper

Long wavelength infrared (LWIR) AOTF and AOM modulators using Hg2Br2 crystals

Priyanthi Amarasinghe, Joo-Soo Kim, Sudhir Trivedi, Jolanta Soos, Mark Diestler, Feng Jin, Syed Qadri, Neelam Gupta, Janet Jensen, James Jensen

Proceedings Volume 10404, 104040T (2017) https://doi.org/10.1117/12.2279160

KEYWORDS: Crystals, Long wavelength infrared, Bragg cells, Acousto-optics, Single crystal X-ray diffraction, X-ray diffraction, Tunable filters, Diffraction

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SPIE Journal Paper | 20 July 2017

Effects of sidelobes on acousto-optic tunable filter imaging

Neelam Gupta, Dennis Suhre

OE, Vol. 56, Issue 07, 073106, (July 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.7.073106

KEYWORDS: Acousto-optics, Tunable filters, Imaging systems, Hyperspectral imaging, Infrared imaging, Infrared radiation, Image transmission, Ultraviolet radiation, Long wavelength infrared, Transducers

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Proceedings Article | 16 February 2017 Presentation + Paper

Sidelobe considerations in AOTF imaging

Neelam Gupta, Dennis Suhre

Proceedings Volume 10100, 101000L (2017) https://doi.org/10.1117/12.2252277

KEYWORDS: Hyperspectral imaging, Imaging systems, Short wave infrared radiation, Transducers, Acoustics, Crystals, Semiconductor lasers, Cameras, Confocal optics, Optical filters

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An acousto-optic tunable filter (AOTF) is an all solid-state robust device with no-moving parts that has been used in the development of hyperspectral imagers from the ultraviolet to the longwave infrared. Such a device is fabricated by bonding a piezoelectric transducer on a specially cut prism in a birefringent crystal. When a radio frequency (RF) signal is applied to the transducer, a diffraction grating is set up in the crystal with grating period determined by the applied RF and the diffracted wavelength depends upon the applied RF and the prism parameters. When broadband white light is incident on the prism input facet, two orthogonally polarized diffracted beams at a specific wavelength with a narrow bandpass are transmitted for each applied RF. The transmitted wavelength can be tuned by varying the applied RF and this is used in a hyperspectral imager design. The spectral response of the transmitted intensity from an AOTF with a rectangular transducer has a sinc² distribution with a main lobe and a large number of sidelobes. In general, in hyperspectral imaging applications the light leakage from the sidelobes is not taken into account. When imaging is carried out for a scene with a laser or an intense source of light, the spectral images are affected by the light transmitted through these sidelobes away from the main lobe. We have carried out a detailed study of light transmitted through the sidelobes of a TeO₂ AOTF with a rectangular transducer operating in the shortwave infrared (SWIR) region from 0.9 to 1.7 μm. The AOTF imaging system used a telecentric confocal optics that compensates for AOTF aberrations, which are severe at high sidelobe operation. We used a 16-channel RF driver with independent amplitude and frequency control. By switching off specific RF signals applied to the AOTF, we measured the detailed sidelobe structure for the transmitted intensity by analyzing the spectral images and compared it with theoretical prediction. Here we present our experimental setup and results.

Proceedings Article | 17 May 2016 Paper

Acousto-optic tunable filter as a notch filter

Neelam Gupta

Proceedings Volume 9822, 982212 (2016) https://doi.org/10.1117/12.2224238

KEYWORDS: Acousto-optics, Short wave infrared radiation, Linear filtering, Hyperspectral imaging, Imaging systems, Transducers, Crystals, Optical filters, Acoustics, Cameras

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Proceedings Article | 12 May 2016 Paper

Long wave infrared tunable filter based on guided mode resonant effect

Mark Mirotznik, Neelam Gupta, Morgan McElhiney, Victoria Carey

Proceedings Volume 9855, 98550L (2016) https://doi.org/10.1117/12.2229484

KEYWORDS: Long wavelength infrared, Dielectrics, Infrared radiation, Dielectric filters, Optical filters, Tunable filters, Waveguides, Germanium, Reflectivity, Polarization

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Proceedings Article | 24 February 2016 Paper

Design and fabrication of long wave infrared spectral filters

Victoria Carey, Morgan McElhiney, Neelam Gupta, Janet Jensen, Dennis Prather, Mark Mirotznik

Proceedings Volume 9744, 97441F (2016) https://doi.org/10.1117/12.2213157

KEYWORDS: Optical filters, Infrared radiation, Long wavelength infrared, Reflectivity, Germanium, Mirrors, Dielectric polarization, Plasmonics, Absorption filters, Reflection

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Proceedings Article | 26 August 2015 Paper

Novel semiconductor radiation detector based on mercurous halides

Henry Chen, Joo-Soo Kim, Proyanthi Amarasinghe, Withold Palosz, Feng Jin, Sudhir Trivedi, Arnold Burger, Jarrod Marsh, Marc Litz, Priyalal Wiejewarnasuriya, Neelam Gupta, Janet Jensen, James Jensen

Proceedings Volume 9593, 95930G (2015) https://doi.org/10.1117/12.2188448

KEYWORDS: Sensors, Crystals, Commercial off the shelf technology, Sensor performance, Electrodes, Bromine, Electrons, Semiconductors, Chlorine, Homeland security

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Proceedings Article | 3 June 2015 Paper

Performance characterization of VNIR and SWIR spectropolarimetric imagers

Neelam Gupta

Proceedings Volume 9482, 948216 (2015) https://doi.org/10.1117/12.2177099

KEYWORDS: Imaging systems, Polarization, Short wave infrared radiation, Cameras, Crystals, Reflectivity, Hyperspectral imaging, Acousto-optics, Tunable filters, Acoustics

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Proceedings Article | 27 February 2015 Paper

Large size MOEMS Fabry-Perot interferometer filter for focal plane array hyperspectral imaging

J. Chee, J. Hwu, T. Kim, J. Kubby, S. Velicu, N. Gupta

Proceedings Volume 9375, 93750K (2015) https://doi.org/10.1117/12.2076615

KEYWORDS: Electronic filtering, Staring arrays, Microopto electromechanical systems, Silicon, Electrodes, Computer aided design, Fabry–Perot interferometry, Hyperspectral imaging, Optical filters, Long wavelength infrared

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Proceedings Article | 21 May 2014 Paper

Miniaturized imaging spectrometer based on Fabry-Perot MOEMS filters and HgCdTe infrared focal plane arrays

S. Velicu, C. Buurma, J. Bergeson, Tae Sung Kim, J. Kubby, N. Gupta

Proceedings Volume 9100, 91000F (2014) https://doi.org/10.1117/12.2053902

KEYWORDS: Electronic filtering, Reflectivity, Spectroscopy, Semiconducting wafers, Infrared imaging, Infrared radiation, Interfaces, Staring arrays, Long wavelength infrared, Spectral resolution

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Imaging spectrometry can be utilized in the midwave infrared (MWIR) and long wave infrared (LWIR) bands to detect, identify and map complex chemical agents based on their rotational and vibrational emission spectra. Hyperspectral datasets are typically obtained using grating or Fourier transform spectrometers to separate the incoming light into spectral bands. At present, these spectrometers are large, cumbersome, slow and expensive, and their resolution is limited by bulky mechanical components such as mirrors and gratings. As such, low-cost, miniaturized imaging spectrometers are of great interest. Microfabrication of micro-electro-mechanicalsystems (MEMS)-based components opens the door for producing low-cost, reliable optical systems. We present here our work on developing a miniaturized IR imaging spectrometer by coupling a mercury cadmium telluride (HgCdTe)-based infrared focal plane array (FPA) with a MEMS-based Fabry-Perot filter (FPF). The two membranes are fabricated from silicon-oninsulator (SOI) wafers using bulk micromachining technology. The fixed membrane is a standard silicon membrane, fabricated using back etching processes. The movable membrane is implemented as an X-beam structure to improve mechanical stability. The geometries of the distributed Bragg reflector (DBR)-based tunable FPFs are modeled to achieve the desired spectral resolution and wavelength range. Additionally, acceptable fabrication tolerances are determined by modeling the spectral performance of the FPFs as a function of DBR surface roughness and membrane curvature. These fabrication non-idealities are then mitigated by developing an optimized DBR process flow yielding high-performance FPF cavities. Zinc Sulfide (ZnS) and Germanium (Ge) are chosen as the low and the high index materials, respectively, and are deposited using an electron beam process. Simulations are presented showing the impact of these changes and non-idealities in both a device and systems level.

Proceedings Article | 21 May 2014 Paper

Materials for imaging acousto-optic tunable filters

Neelam Gupta

Proceedings Volume 9100, 91000C (2014) https://doi.org/10.1117/12.2054050

KEYWORDS: Crystals, Transducers, Acoustics, Imaging systems, Optical filters, Acousto-optics, Long wavelength infrared, Hyperspectral imaging, Cameras, Ultraviolet radiation

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Proceedings Article | 21 May 2014 Paper

Development of spectropolarimetric imagers from 400 to 1700 nm

Neelam Gupta

Proceedings Volume 9099, 90990N (2014) https://doi.org/10.1117/12.2052947

KEYWORDS: Imaging systems, Polarization, Wave plates, Crystals, Short wave infrared radiation, Cameras, Calibration, Liquid crystals, Hyperspectral imaging, Phase shifts

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SPIE Journal Paper | 13 March 2014

Design and fabrication of Fabry–Perot filters for infrared hyperspectral imagers

Michael Morley, Silviu Velicu, Yong Chang, Christoph Grein, Dmitry Kozak, Bautista Fernandez, Joel Kubby, Neelam Gupta

JM3, Vol. 13, Issue 01, 011116, (March 2014) https://doi.org/10.1117/12.10.1117/1.JMM.13.1.011116

KEYWORDS: Electronic filtering, Reflectivity, Infrared imaging, Hyperspectral imaging, Imaging systems, Optical filters, Infrared radiation, Semiconducting wafers, Image filtering, Surface roughness

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Proceedings Article | 7 March 2014 Paper

Next generation miniature simultaneous multi-hyperspectral imaging systems

Michele Hinnrichs, Neelam Gupta

Proceedings Volume 8977, 89770D (2014) https://doi.org/10.1117/12.2035244

KEYWORDS: Mirrors, Fabry–Perot interferometers, Gold, Tunable filters, Microopto electromechanical systems, Hyperspectral imaging, Staring arrays, Spectral resolution, Cameras, Signal detection

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Proceedings Article | 4 June 2013 Paper

Characterization of SWIR hyperspectral imager with a multispectral polarized scene projector

Neelam Gupta

Proceedings Volume 8707, 870706 (2013) https://doi.org/10.1117/12.2014325

KEYWORDS: Imaging systems, Hyperspectral imaging, Polarization, Projection systems, Spatial light modulators, Short wave infrared radiation, Cameras, Liquid crystal on silicon, Tunable filters, Indium gallium arsenide

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Proceedings Article | 5 March 2013 Paper

Hyperspectral Fabry-Perot filters for HgCdTe infrared detectors

Yong Chang, Christoph Grein, Silviu Velicu, Michael Morley, Neelam Gupta

Proceedings Volume 8613, 861316 (2013) https://doi.org/10.1117/12.2007508

KEYWORDS: Electronic filtering, Long wavelength infrared, Reflectivity, Spectral resolution, Mercury cadmium telluride, Interfaces, Optical filters, Sensors, Infrared detectors, Zinc

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SPIE Journal Paper | 19 July 2012

Microelectromechanical systems-based visible-near infrared Fabry-Perot tunable filters using quartz substrate

Neelam Gupta, Songsheng Tan, Dennis Zander

OE, Vol. 51, Issue 7, 074007, (July 2012) https://doi.org/10.1117/12.10.1117/1.OE.51.7.074007

KEYWORDS: Mirrors, Silver, Electrodes, Quartz, Tunable filters, Microelectromechanical systems, Fabry–Perot interferometers, Infrared imaging, Optical filters, Gold

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SPIE Journal Paper | 16 July 2012

Spectral imaging characterization of quartz MOEM tunable Fabry-Perot filter

Neelam Gupta, Songsheng Tan

JM3, Vol. 11, Issue 3, 033002, (July 2012) https://doi.org/10.1117/12.10.1117/1.JMM.11.3.033002

KEYWORDS: Optical filters, Mirrors, Image filtering, Tunable filters, Microopto electromechanical systems, Electrodes, Quartz, Imaging spectroscopy, Imaging systems, Fabry–Perot interferometers

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Proceedings Article | 16 February 2012 Paper

Spectral imaging characterization of MOEM tunable Fabry-Perot filter

Neelam Gupta

Proceedings Volume 8252, 82520E (2012) https://doi.org/10.1117/12.908428

KEYWORDS: Mirrors, Optical filters, Image filtering, Microopto electromechanical systems, Tunable filters, Electrodes, Silver, Hyperspectral imaging, Imaging systems, Fabry–Perot interferometers

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Proceedings Article | 13 May 2011 Paper

Multispectral polarized scene projector (MPSP)

Haiping Yu, Hong Wei, Lei Guo, Shenggang Wang, Le Li, Jack Lippert, Steve Serati, Neelam Gupta, Frank Carlen

Proceedings Volume 8015, 801506 (2011) https://doi.org/10.1117/12.887028

KEYWORDS: Polarization, Spatial light modulators, Nonuniformity corrections, Sensors, Polarimetry, Tunable filters, Liquid crystal on silicon, Projection systems, Short wave infrared radiation, Liquid crystals

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Proceedings Article | 12 May 2011 Paper

MEMS-based tunable Fabry-Perot filters

Neelam Gupta, Songsheng Tan, Dennis Zander

Proceedings Volume 8032, 803205 (2011) https://doi.org/10.1117/12.881649

KEYWORDS: Mirrors, Tunable filters, Silver, Semiconducting wafers, Electrodes, Fabry–Perot interferometers, Optical filters, Quartz, Gold, Transmittance

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SPIE Journal Paper | 1 March 2011

Miniature snapshot multispectral imager

Neelam Gupta, Philip Ashe, Songsheng Tan

OE, Vol. 50, Issue 03, 033203, (March 2011) https://doi.org/10.1117/12.10.1117/1.3552665

KEYWORDS: Optical filters, Image filtering, Imaging systems, Multispectral imaging, Cameras, Staring arrays, Microlens, Dielectric filters, Optical fabrication, Mirrors

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Proceedings Article | 4 May 2010 Paper

A miniature snapshot multispectral imager

Neelam Gupta, Philip Ashe, Songsheng Tan

Proceedings Volume 7660, 76602G (2010) https://doi.org/10.1117/12.852661

KEYWORDS: Optical filters, Imaging systems, Image filtering, Cameras, Dielectric filters, Staring arrays, Multispectral imaging, Silica, Fabry–Perot interferometers, Microlens

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Proceedings Article | 5 May 2009 Paper

Development of an unattended ground sensor array using piezoresistive sensors

Kelly Lee, Neelam Gupta, Ronald Sartain

Proceedings Volume 7333, 733316 (2009) https://doi.org/10.1117/12.817276

KEYWORDS: Sensors, Resistors, Resistance, Metals, Unattended ground sensors, Piezoresistive sensors, Software development, Roads, Carbon, Electronics

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This paper discusses the development of an Unattended Ground Sensor based on an array of pressure sensors designed to be buried in the ground. This sensor array, along with the required software (still under development), will have the ability to distinguish between humans and animals based on the size and shape of the foot print. The technology may also be applied to determine the weight and type of vehicle traveling on a road. The sensor array consists of pressure sensitive resistors (piezoresistors) on 0.8 inch centers printed on a sheet of polyimide film. Although very large arrays might one day be screen printed, the arrays for this study have been printed using a syringe dispenser and a precision x-y computer controlled table. For the preliminary development, the array has been sized to 8X10 inches. The piezoresistive properties of the sensors are discussed and preliminary test data is presented. It is shown that the piezoresistive gauge factor (ΔR/R/ΔL/L) is roughly 10 times that of conventional metal strain gauges. Because the change in resistance is large compared to metal strain gauges, lower cost electronics can be used. The small net size and low mass enables sensing elements with fast response time. The fact that these piezoresistive elements are directly printed, as opposed to being adhesively attached to a surface, eliminates many of the issues associated with bonded discrete sensors. It is anticipated that the piezoresistive sensor approach presented in this paper will be well suited to extremely rugged environmental conditions compared to the commercially available sensor arrays which rely on surface contact resistance or capacitive sensors which can be easily destroyed by moisture. Environmental testing will be done in a future phase of the project. The final system, which is still under development, will consist of a sensor array, information processing, and RF signal transmission. The system is anticipated to be low cost and environmentally rugged.

Proceedings Article | 5 May 2009 Paper

LWIR hyperspectral imager based on a diffractive optics lens

Neelam Gupta

Proceedings Volume 7303, 730314 (2009) https://doi.org/10.1117/12.817773

KEYWORDS: Imaging systems, Staring arrays, Silicon, Long wavelength infrared, Hyperspectral imaging, Absorption, Cameras, Image processing, Aluminum, Image analysis

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Proceedings Article | 16 April 2008 Paper

Hyperspectral imager development at Army Research Laboratory

Neelam Gupta

Proceedings Volume 6940, 69401P (2008) https://doi.org/10.1117/12.777110

KEYWORDS: Imaging systems, Hyperspectral imaging, Staring arrays, Long wavelength infrared, Mid-IR, Fabry–Perot interferometers, Tunable filters, Polarization, Cameras, Ultraviolet radiation

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Development of robust compact optical imagers that can acquire both spectral and spatial features from a scene of interest is of utmost importance for standoff detection of chemical and biological agents as well as targets and backgrounds. Spectral features arise due to the material properties of objects as a result of the emission, reflection, and absorption of light. Using hyperspectral imaging one can acquire images with narrow spectral bands and take advantage of the characteristic spectral signatures of different materials making up the scene in detection of objects. Traditional hyperspectral imaging systems use gratings and prisms that acquire one-dimensional spectral images and require relative motion of sensor and scene in addition to data processing to form a two-dimensional image cube. There is much interest in developing hyperspectral imagers using tunable filters that acquire a two-dimensional spectral image and build up an image cube as a function of time. At the Army Research Laboratory (ARL), we are developing hyperspectral imagers using a number of novel tunable filter technologies. These include acousto-optic tunable filters (AOTFs) that can provide adaptive no-moving-parts imagers from the UV to the long wave infrared, diffractive optics technology that can provide image cubes either in a single spectral region or simultaneously in different spectral regions using a single moving lens or by using a lenslet array, and micro-electromechanical systems (MEMS)-based Fabry-Perot (FP) tunable etalons to develop miniature sensors that take advantage of the advances in microfabrication and packaging technologies. New materials are being developed to design AOTFs and a full Stokes polarization imager has been developed, diffractive optics lenslet arrays are being explored, and novel FP tunable filters are under fabrication for the development of novel miniature hyperspectral imagers. Here we will brief on all the technologies being developed and present highlights of our research and development efforts.

Proceedings Article | 16 April 2008 Paper

Comparison of QWIP to HgCdTe detectors for gas imaging

Michele Hinnrichs, Neelam Gupta

Proceedings Volume 6940, 69401Q (2008) https://doi.org/10.1117/12.779322

KEYWORDS: Sensors, Quantum well infrared photodetectors, Mercury cadmium telluride, Detector arrays, Imaging spectroscopy, Absorption, Spectrometers, Imaging systems, Aerosols, Image sensors

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Proceedings Article | 31 March 2008 Paper

Acousto-optic tunable filter based spectropolarimetric imagers

Neelam Gupta

Proceedings Volume 6972, 69720C (2008) https://doi.org/10.1117/12.782800

KEYWORDS: Imaging systems, Polarization, Cameras, Crystals, Hyperspectral imaging, Tunable filters, Wave plates, Acousto-optics, Acoustics, Ultraviolet radiation

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Proceedings Article | 8 February 2008 Paper

Detection of blood oxygen level by noninvasive passive spectral imaging of skin

Neelam Gupta, Jessica Ramella-Roman

Proceedings Volume 6842, 68420C (2008) https://doi.org/10.1117/12.768708

KEYWORDS: Imaging systems, Polarization, Skin, Crystals, Acoustics, Hyperspectral imaging, Imaging spectroscopy, Liquid crystals, Wave plates, Transducers

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Proceedings Article | 12 September 2007 Paper

Development of mercurous halide crystals for acousto-optic devices

Joo-Soo Kim, Sudhir Trivedi, Jolanta Soos, Neelam Gupta, Witold Palosz

Proceedings Volume 6661, 66610B (2007) https://doi.org/10.1117/12.734102

KEYWORDS: Crystals, Mercury, Chlorine, Acousto-optics, Bragg cells, Bromine, Transducers, Acoustics, Long wavelength infrared, Transparency

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SPIE Journal Paper | 1 June 2007

Crystal growth, fabrication, and design of mercurous bromide acousto-optic tunable filters

David Knuteson, Narsingh Singh, M. Gottlieb, D. Suhre, Neelam Gupta, Andre Berghmans, David Kahler, Brian Wagner, Jack Hawkins

OE, Vol. 46, Issue 06, 064001, (June 2007) https://doi.org/10.1117/12.10.1117/1.2744369

KEYWORDS: Crystals, Acousto-optics, Mercury, Bromine, Transducers, Acoustics, Tunable filters, X-rays, Polishing, Single crystal X-ray diffraction

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Proceedings Article | 15 February 2006 Paper

Fiber-coupled AOTF spectrometers

Neelam Gupta

Proceedings Volume 6083, 60830U (2006) https://doi.org/10.1117/12.663002

KEYWORDS: Acousto-optics, Adaptive optics, Crystals, Optical fibers, Spectrometers, Quartz, Acoustics, Ultraviolet radiation, Raman spectroscopy, Sensors

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Proceedings Article | 8 November 2005 Paper

A simultaneous dual-band infrared hyperspectral imager for standoff detection

Neelam Gupta, Dale Smith

Proceedings Volume 5995, 59950L (2005) https://doi.org/10.1117/12.641235

KEYWORDS: Imaging systems, Mid-IR, Long wavelength infrared, Image processing, Staring arrays, Hyperspectral imaging, Infrared imaging, Cameras, Standoff detection, Absorption

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Proceedings Article | 29 September 2005 Paper

Acousto-optic tunable filters for infrared imaging

Neelam Gupta

Proceedings Volume 5953, 59530O (2005) https://doi.org/10.1117/12.641081

KEYWORDS: Imaging systems, Crystals, Long wavelength infrared, Hyperspectral imaging, Acousto-optics, Infrared imaging, Cameras, Mercury, Staring arrays, Mid-IR

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Proceedings Article | 9 September 2005 Paper

Design and fabrication of mercurous bromide acousto-optic filters

D. Knuteson, N. Singh, N. Gupta, M. Gottlieb, D. Suhre, A. Berghmans, D. Thomson, D. Kahler, B. Wagner, J. Hawkins, M. Fitelson

Proceedings Volume 5881, 58810E (2005) https://doi.org/10.1117/12.620115

KEYWORDS: Crystals, Acousto-optics, Mercury, Bromine, Transducers, Tunable filters, X-rays, Long wavelength infrared, Acoustics, Transparency

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Proceedings Article | 7 September 2005 Paper

Data collection with a dual-band infrared hyperspectral imager

Dale Smith, Neelam Gupta

Proceedings Volume 5881, 588106 (2005) https://doi.org/10.1117/12.617540

KEYWORDS: Long wavelength infrared, Mid-IR, Imaging systems, Staring arrays, Hyperspectral imaging, Image processing, Infrared imaging, Infrared radiation, Deconvolution, Cameras

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SPIE Journal Paper | 1 September 2005 Open Access

Acousto-optic-tunable-filter-based spectropolarimetric imagers for medical diagnostic applications—instrument design point of view

Neelam Gupta

JBO, Vol. 10, Issue 05, 051802, (September 2005) https://doi.org/10.1117/12.10.1117/1.2102507

KEYWORDS: Imaging systems, Polarization, Ultraviolet radiation, Long wavelength infrared, Hyperspectral imaging, Crystals, Cameras, Medical diagnostics, Biomedical optics, Wave plates

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SPIE Journal Paper | 1 September 2005

Long-wave infrared spectral imager with an 8-cm^–1 passband acousto-optic tunable filter

Dennis Suhre, Neelam Gupta, Milton Gottlieb

OE, Vol. 44, Issue 09, 094601, (September 2005) https://doi.org/10.1117/12.10.1117/1.2048755

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Proceedings Article | 4 August 2004 Paper

Design and fabrication of 2xD light emitting device arrays for IR scene projection

Naresh Das, George Simonis, John Bradshaw, Arnie Goldberg, Neelam Gupta

Proceedings Volume 5408, (2004) https://doi.org/10.1117/12.564347

KEYWORDS: Light emitting diodes, Temperature metrology, Resistors, Infrared cameras, Infrared radiation, Gallium antimonide, Black bodies, Analytical research, Sensors, Light

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Proceedings Article | 27 February 2004 Paper

A no-moving-parts UV/visible hyperspectral imager

Neelam Gupta

Proceedings Volume 5268, (2004) https://doi.org/10.1117/12.517248

KEYWORDS: Imaging systems, Crystals, Hyperspectral imaging, Ultraviolet radiation, CCD cameras, Optical filters, Quartz, Acoustics, Transducers, Acousto-optics

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Proceedings Article | 27 February 2004 Paper

Mid-wave IR liquid crystal tunable retarder for spectrapolarimetric imaging

Narasimha Prasad, Kenneth Arnett, Neelam Gupta

Proceedings Volume 5268, (2004) https://doi.org/10.1117/12.519645

KEYWORDS: Liquid crystals, Mid-IR, Wave plates, Imaging systems, Absorption, Spinel, Black bodies, Polarization, Birefringence, Coating

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SPIE Journal Paper | 1 May 2002

Acousto-optic tunable filter-based visible-to-near-infrared spectroploarimetric imager

Neelam Gupta, Rachid Dahmani, Steven Choy

OE, Vol. 41, Issue 05, (May 2002) https://doi.org/10.1117/12.10.1117/1.1467936

KEYWORDS: Polarization, Imaging systems, Acousto-optics, Crystals, Tunable filters, Roads, Cameras, Acoustics, CCD cameras, Spectral resolution

Proceedings Article | 7 February 2002 Paper

Tunable acousto-optic filters for monitoring of atmospheric ozone

Vitaly Voloshinov, Neelam Gupta

Proceedings Volume 4574, (2002) https://doi.org/10.1117/12.455155

KEYWORDS: Acousto-optics, Crystals, Optical filters, Ultraviolet radiation, Quartz, Signal to noise ratio, Acoustics, Atmospheric monitoring, Adaptive optics, Earth's atmosphere

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Proceedings Article | 7 February 2002 Paper

Remote sensing using hyperspectral and polarization images

Neelam Gupta

Proceedings Volume 4574, (2002) https://doi.org/10.1117/12.455158

KEYWORDS: Imaging systems, Polarization, Hyperspectral imaging, Infrared imaging, Remote sensing, Long wavelength infrared, Tunable filters, Wave plates, Staring arrays, Infrared signatures

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Proceedings Article | 7 February 2002 Paper

Spectroscopic analysis of automotive engine oil

Rachid Dahmani, Neelam Gupta

Proceedings Volume 4574, (2002) https://doi.org/10.1117/12.455157

KEYWORDS: Spectroscopy, Absorption, Infrared spectroscopy, FT-IR spectroscopy, Absorption spectroscopy, Atmospheric particles, Acousto-optics, Chemical analysis, Metals, Analytical research

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Proceedings Article | 15 November 2000 Paper

Spectropolarimetric imaging using a field-portable imager

Neelam Gupta, Louis Denes, Milton Gottlieb, Dennis Suhre, Boris Kaminsky, Peter Metes

Proceedings Volume 4132, (2000) https://doi.org/10.1117/12.406607

KEYWORDS: Polarization, Imaging systems, Metals, Vegetation, Roads, Polarimetry, Analytical research, Visible radiation, Target detection, Acousto-optics

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Proceedings Article | 27 July 2000 Paper

Progress in AOTF hyperspectral imagers

Neelam Gupta, Rachid Dahmani, Kelly Bennett, S. Simizu, Dennis Suhre, N. Singh

Proceedings Volume 4054, (2000) https://doi.org/10.1117/12.394104

KEYWORDS: Imaging systems, Hyperspectral imaging, Crystals, Long wavelength infrared, Staring arrays, Sensors, Infrared imaging, Thallium, Polarization, Mercury cadmium telluride

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Proceedings Article | 24 September 1999 Paper

Acousto-optic imaging in the mid-infrared region of the spectrum

Vitaly Voloshinov, Neelam Gupta

Proceedings Volume 3900, (1999) https://doi.org/10.1117/12.364573

KEYWORDS: Acousto-optics, Optical filters, Acoustics, Crystals, Transducers, Infrared radiation, Image filtering, Infrared imaging, Image processing, Diffraction

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Proceedings Article | 24 August 1999 Paper

Hyperspectral imaging using acousto-optic tunable filters

Neelam Gupta, Rachid Dahmani, Milton Gottlieb, Louis Denes, Boris Kaminsky, Peter Metes

Proceedings Volume 3718, (1999) https://doi.org/10.1117/12.359988

KEYWORDS: Imaging systems, Hyperspectral imaging, Polarization, Image processing, Acousto-optics, Optical filters, Polarimetry, Camouflage, Tunable filters, Image filtering

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Proceedings Article | 29 January 1999 Paper

Multispectral and hyperspectral imaging with AOTF for object recognition

Neelam Gupta, Rachid Dahmani

Proceedings Volume 3584, (1999) https://doi.org/10.1117/12.339814

KEYWORDS: Imaging systems, Hyperspectral imaging, Multispectral imaging, Crystals, Acoustics, Image processing, Acousto-optics, Polarization, Optical filters, Mid-IR

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Proceedings Article | 1 July 1993 Paper

GaAs-waveguide-based optical neural network device architecture

Neelam Gupta, John Pham

Proceedings Volume 1849, (1993) https://doi.org/10.1117/12.147082

KEYWORDS: Neurons, Waveguides, Modulators, Gallium arsenide, Optoelectronics, Semiconductor lasers, Stereolithography, Neural networks, Switches, Resistors

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Proceedings Article | 1 June 1990 Paper

Lithium niobate integrated-optics demonstration of optical control of microwaves

Neelam Gupta, George Simonis, Paul Ashley

Proceedings Volume 1217, (1990) https://doi.org/10.1117/12.18148

KEYWORDS: Waveguides, Phased array optics, Integrated optics, Microwave radiation, Bragg cells, Phase shifts, Antennas, Lithium niobate, Signal detection, Sensors

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