Dr. Narasimha S. Prasad Profile

Dr. Narasimha S. Prasad

Aerospace Technologist at NASA Langley Research Ctr

SPIE Involvement:

Conference Program Committee | Author | Editor

Publications (101)

Proceedings Article | 13 April 2024 Presentation

Design and low temperature flux growth of multifunctional optical crystals

Narasimha Prasad, Ching Hua Su, Meghan Brandt, Aria Tauraso, Krishna Machuga, Bradley Arnold, Fow-Sen Choa, Brian Cullum, Narsingh Singh

Proceedings Volume PC12882, PC1288205 (2024) https://doi.org/10.1117/12.3003480

KEYWORDS: Crystals, Mid-IR, Long wavelength infrared, Design and modelling, Crystal optics, Gallium, Transparency, Thermal stability, Polishing, Nonlinear optics

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SPIE Journal Paper | 19 March 2024

Effect of high-energy radiation on the electrical and optical characteristics of bioactive glasses

Aria Tauraso, Krishna Machuga, Joel McAdams, Ching Hua Su, Brian Cullum, Tagide deCarvalho, Narasimha Prasad, Bradley Arnold, Fow-Sen Choa, Kamdeo Mandal, Narsingh Bahadur Singh

OE, Vol. 63, Issue 03, 037105, (March 2024) https://doi.org/10.1117/12.10.1117/1.OE.63.3.037105

KEYWORDS: Glasses, Radiation effects, Dielectrics, Titanium, Mixtures, Selenium, Silicates, Phosphates, Oxides, Crystals

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Proceedings Article | 13 March 2024 Presentation + Paper

Resolving wave-particle duality could accelerate the mass production of quantum computers

Chandrasekhar Roychoudhuri, Narasimha Prasad

Proceedings Volume 12911, 129110H (2024) https://doi.org/10.1117/12.3001213

KEYWORDS: Quantum processes, Photons, Quantum detection, Sensors, Quantum light, Spectroscopy, Quantum superposition, Quantum physics, Quantum amplitude, Signal detection

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Quantum computers, hypothesized in 1980s, use concepts of superposition and entanglement phenomena. Although theoretical propositions and associated search algorithms for accurate measurements are being generated, the development of practical quantum computers themselves are advancing very slowly requiring enormous time and investments. The underlying concepts of a quantum computer are not new to the optical domain. However, the crucial enabling concepts of Entanglement and Superposition Principle are remaining clouded under the unresolved postulates, Wave-Particle Duality (WPD), and Wave Packet Reduction (WPR), implicating incompleteness in the interpretations of the mathematical formalism behind Quantum Mechanics. The WPD debate started during late1600 between Newton and Huygens. Young’s resolution of WPD through his double-slit experiment in 1802 was effectively overturned by Einstein’s interpretation of photoelectric effect as due to “indivisible light quanta”. However, Einstein disowned his “light quanta” postulate shortly before his death in1955, even though it had earned him the Nobel Prize. We resolve WPD by synthesizing Newton’s and Maxwell’s concepts and assume atoms do emit quanta but propagate as time-finite exponential pulses. This assumption also resolves WPR for light-matter interaction with the assumption that Schrodinger’s ψ represents atom’s internal dipolar amplitude stimulations. This over-turns Born’s interpretation that ψ only represents the abstract mathematical probability amplitude, rather than the physical “internal amplitude stimulation” of the quantum entity. However, our concept of atomic pulse emission forces us to re-derive the expression for the N-slit grating-spectrometer response since the classical derivation uses CW light, which does not exist. This pulsespectrometric response function strengthens our postulate since the grating response to the exponential pulse appears to be the convolution of a Lorentzian spectrum with the classical CW response function of the grating. The Fourier Transform of an exponential function is Lorentzian and QM predicts spontaneous emission line width to be Lorentzian. Then, conceptually one can extend the grating-expression (with N=2) to get the double-slit pattern. This approach preserves the classical causality that each of the two slits, like the N-signals out of a grating, are physically real and jointly stimulate the quantum detector array at the far field to generate the “Local” cosine fringes. The detector array executes the square modulus operation on its imposed dipolar amplitude stimulation and absorbs the necessary energy to fill up their quantum cups. Hence the double-slit pattern must also be “Local”, just as the N-slit grating spectrum is generated locally at the exit spectral-plane of the spectrometer. This removes the need to believe that “single photons” mysteriously generate the double slit pattern.

Proceedings Article | 12 March 2024 Presentation + Paper

Space qualification studies of AOTF devices under the MISSE-11 mission

Narasimha Prasad, Sudhir Trivedi, Priyanthi Amarasinghe, Feng Jin, Mark Distler, Joo Soo Kim, Hayden Diener

Proceedings Volume 12864, 1286408 (2024) https://doi.org/10.1117/12.3003450

KEYWORDS: Acoustooptic tunable filters, Mercury, Bromine, Diffraction, Crystals, Space operations, Long wavelength infrared, Short wave infrared radiation, Transducers, Optical surfaces

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Proceedings Article | 14 June 2023 Presentation + Paper

Disruptive chemical approach to modify perovskites for chemical and biological sensors

Meghan Brandt, Mahack Kazmi, Ching Hua Su, Narasimha Prasad, Bradley Arnold, Fow-Sen Choa, Brian Cullum, Eric Bowman, Krishna Machuga, N. Singh

Proceedings Volume 12548, 1254804 (2023) https://doi.org/10.1117/12.2661233

KEYWORDS: Dielectrics, Annealing, Sodium, Perovskite, Scanning electron microscopy, Sensors, Capacitance, Acetone, Sintering, Capacitors

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Proceedings Article | 14 June 2023 Presentation + Paper

Effect of processing parameters on sensing of chem-bio agents on surfaces: contact angle-based interactions

Narasimha Prasad, Brett Setera, Ian Emge, Leslie Scheurer, Lisa Kelly, Brad Arnold, Brian Cullum, Fow-Sen Choa, N. Singh

Proceedings Volume 12548, 1254802 (2023) https://doi.org/10.1117/12.2661716

KEYWORDS: Annealing, Polystyrene, Nanoparticles, Sensors, Polymers, Titanium, Particles, Oxides, Mixtures, Materials properties

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Proceedings Article | 8 March 2023 Presentation + Paper

Optical characteristics of radiated multifunctional optical materials

Narasimha Prasad, Eric Bowman, Meghan Brandt, Amalthea Trobare, Ching Hua Su, Bradley Arnold, Fow-Sen Choa, N. Singh

Proceedings Volume 12399, 123990F (2023) https://doi.org/10.1117/12.2653580

KEYWORDS: Electromagnetic radiation, Crystals, Mercury, Acoustooptics, Spectroscopy, Optical filters, Absorbance, Tunable filters, Metals, Laser radiation

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Proceedings Article | 30 September 2022 Presentation + Paper

Where lies the quantumness behind detecting electromagnetic waves for frequencies from infrared and up?

C. Roychoudhuri, N. Prasad, G. Fernando

Proceedings Volume 12233, 122330G (2022) https://doi.org/10.1117/12.2635066

KEYWORDS: Superposition, Sensors, Radio propagation, Visualization, Electromagnetism, Surface plasmons, Wave propagation, Particles, Molecules

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Proceedings Article | 19 July 2022 Presentation + Paper

Understanding physical processes behind the photoelectric current pulse (PCP) statistics and designing better sources

C. Roychoudhuri, G. Fernando, N. Prasad

Proceedings Volume 12243, 1224303 (2022) https://doi.org/10.1117/12.2626319

KEYWORDS: Photons, Sensors, Photodetectors, Superposition, Physics, Light wave propagation, Radio propagation, Wavelets

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A deeper understanding of the physical processes behind the emergence of photoelectron current pulse (PCP) statistics could help relaxing the source requirements for quantum computers, in choosing nonlinear vs. linear processing of light. Einstein’s photoelectric equation is an energy-balancing “bullet model”. The “bullet-model” over-rides both the classical and the quantum Superposition Principle (SP). SP requires first summing the joint amplitude stimulation experienced by the detecting dipoles by all the incident complex amplitudes, followed by the square modulus operation executed by the detecting dipoles to absorb the quantum-cupful of energy. We have been accommodating this “bullet model” via the prevailing belief that wave-particle duality is our new “confirmed knowledge”, instead of acknowledging our ignorance about the true nature of light. We will use the semiclassical model of photons as time-finite random light pulses stimulating a detecting molecule to its excited state of Ѱ. The molecule then absorbs the quantum of energy through the execution of the square modulus operation, Ѱ*Ѱ, and release the quantum mechanically bound electron. The lifetime of releasing the bound electron is very short as they are in quantum bands, rather than in sharp quantum levels. Each one of the released electron is then amplified, through complex electronic processes, by a factor of as much as 109, to generate one easily measurable photoelectric current pulse, or PCP’s. Therefore, the emergence of the PCP statistics is a combined function of (i) fluctuations in the incident light, (ii) fluctuations in the electron emission moments and (iii) noise introduced during the amplification process. In this paper, we will consider a classical linear approach in smoothing the average energy delivery on to a photodetector using the natural pulse replication property of a Fabry-Perot interferometer (FPI) and hence narrow the PCP statistical spread. If our model is correct, we should be able to derive the PCP-statistics for different sources using the fundamental amplitude and phase characteristics of various real sources. We have also proposed specific experiments to validate our model.

Proceedings Article | 12 April 2021 Presentation + Paper

Surface characteristics of polymer nanocomposites

Ian Emge, Leslie Scheurer, Ryan Grant, Narasimha Prasad, Lisa Kelly, Bradley Arnold, Fow-Sen Choa, Brett Setera, N. Singh

Proceedings Volume 11757, 117570X (2021) https://doi.org/10.1117/12.2585834

KEYWORDS: Polymers, Composites, Sensors

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Proceedings Article | 20 August 2020 Presentation

Multifunctional semiconductors for radiation sensors: crystal growth and characterization

Narsingh Bahadur Singh, Ian Emge, Brett Setera, Charmain Su, Fow-Sen Choa, Bradley Arnold, Kamdeo Mandal, Narasimha Prasad

Proceedings Volume 11494, 1149406 (2020) https://doi.org/10.1117/12.2566996

KEYWORDS: Sensors, Crystals, Semiconductors

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Proceedings Article | 2 March 2020 Presentation + Paper

Picosecond pulsewidth direct detection lidar for imaging applications

Narasimha Prasad, Anand Mylapore

Proceedings Volume 11287, 112870J (2020) https://doi.org/10.1117/12.2548003

KEYWORDS: LIDAR, 3D image processing, Polygon scanners, 3D metrology, Scanners, 3D acquisition, Sensors, Electronics, Data acquisition

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Proceedings Article | 13 February 2020 Paper

Advanced SWIR photon-sensing integrated circuit hetero-junction phototransistor based focal plane array for space applications

Narasimha Prasad, Yin Liu, Feng Sun, Jie Yao

Proceedings Volume 11288, 1128804 (2020) https://doi.org/10.1117/12.2550032

KEYWORDS: Staring arrays, Short wave infrared radiation, Space operations, Ionization, Indium gallium arsenide, Sensors, Imaging systems, Signal to noise ratio, Photonic integrated circuits, Integrated circuits

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Uncooled focal plane arrays (FPA) with reduced size, weight, and power consumption (SWaP) features and coupled with enhanced characteristics have the potential to significantly benefit a wide range of imaging applications including space surveillance from terrestrial and space-based platforms and planetary composition mapping for space exploration missions. Recently, an innovative, uncooled Photon-Sensing Integrated Circuit (PSIC) hetero-junction phototransistor (HPT) device has been developed. This InGaAs based PSIC HPT device is a room temperature detector and imager that is of 320 x 256 pixel format with 30 micron pixels, and operates in the short-wave infrared (SWIR) spectral region of 0.9 to 1.7 microns. It is a continuously operating (i.e., zero recovery time), zero-excess-noise and linear-mode (i.e., capable of representing photon numbers) photon-sensing detector and imager. Enabled by its hetero-junction phototransistor (HPT) amplification instead of the conventional avalanche multiplication mechanism, this InGaAs HPT simultaneously exhibits signal amplification gain of >1000, namely, >20 x higher gain, and <1/10 lower dark current areal density than InGaAs avalanche photodiode (APD). The photon transfer data (relationship between signal, noise and photon number) for this PSIC imager at FPA mean value and at room temperature is approximately 0.2 noise-equivalent photons per pixel per frame measured using a readout Integrated circuit (ROIC) with 350-700 electron readout noise. The measured uncooled specific detectivity, D* of 3E14 cm.Hz/W appears to be higher than those available commercially. The current HPTs exhibit higher speed, higher gain, lower dark current and noise, and hence achieve highest signal-to-noise ratio (SNR) for photon detection. Recently, the prototype device was selected for space qualification studies on the international space station (ISS). Under NASA’s MISSE-11 (Materials International Space Station Experiment) mission, this device was integrated on to a carrier with various other test components and was launched in April 2019. In this paper, salient features of material processing, device configuration and packaging architecture followed by the pre-flight performance tests carried out will be presented.

Proceedings Article | 31 January 2020 Presentation + Paper

Contrasting quantum sensing light source properties, which generate different photocurrent pulse-statistics

C. Roychoudhuri, G. Fernando, N. Tirfessa, N. Prasad

Proceedings Volume 11288, 112880F (2020) https://doi.org/10.1117/12.2551090

KEYWORDS: Photons, Sensors, Physics, Superposition, Statistical modeling, Light sources

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Proceedings Article | 2 May 2019 Presentation + Paper

Importance of lotus effect on surface sensing

Stacey Sova, Narasimha Prasad, Christopher Cooper, Lisa Kelly, Bradley Arnold, Brian Cullum, Fow-Sen Choa, N. B. Singh

Proceedings Volume 11020, 1102005 (2019) https://doi.org/10.1117/12.2519738

KEYWORDS: Nanoparticles, Polymers, Thin films, Polymer thin films, Polymethylmethacrylate, Glasses, Ultraviolet radiation, Absorbance, Scanning electron microscopy, Absorption

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Proceedings Article | 22 March 2019 Presentation + Paper

Complex interaction processes we need to visualize that successfully fill the quantum cup of a detector

Chandrasekhar Roychoudhuri, Narasimha Prasad

Proceedings Volume 10926, 109260T (2019) https://doi.org/10.1117/12.2514835

KEYWORDS: Superposition, Sensors, Chemical species, Beam splitters, Molecules, Wave propagation, Diffraction, Absorption, Visualization, Polarizability

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Sensors are measuring tools. In any measurement, we have at least two different kinds of interactants. We never know all there are to know about any one of these interactants and the interaction processes that are mostly invisible. Yet, our engineering innovation driven evolution is persisting for over five million years. It is then important to articulate explicitly our Interaction Process Mapping Thinking (IPM-T) that we keep applying in the real world without formally recognizing it. We present how the systematic application of IPM-T removes century old wave-particle duality by introducing a model of hybrid photon. It seamlessly bridges the quantum and the classical worlds. Photons are discrete energy packets only at the moment of emission; then they evolve diffractively and propagate as classical waves. Thus, "interference of a single indivisible photon" is only a non-causal assertion. We apply IPM-T to improve the photoelectric equation and we obtain Non-Interaction of Wave (NIW) amplitudes. Note that Huygens explicitly articulated NIW by postulating his "secondary spherical wavelets." Later Fresnel incorporated this postulate in the now famous Huygens- Fresnel (HF) diffraction integral. Most modern optical science and engineering are based upon propagating EM waves through optical devices and systems using this integral in some form or other. Maxwell’s wave equation accepts HF integral as its solution. Systematic application of IPM-T to our causal and working mathematical equations, along with NIW in interferometric experiments, reveal that Superposition Effects can emerge only when the interacting material dipoles respond, whether classically or quantum mechanically, to the joint stimulations due to all the simultaneously superposed waves. This indicates the non-causality of our belief that a single indivisible photon can interfere by itself. We would not have a causally evolving universe had any stable elementary particle were to change itself through selfinterference. Further, our working superposition equations always contain two or more terms representing two or more independently evolving entities. That is why we need physical instruments with two or more independent channels of propagation along with appropriately placed detectors to generate physical superposition effects. Nature does not violate causality. Otherwise, our causally framed equations would not have been working so elegantly.

Proceedings Article | 10 October 2018 Presentation + Paper

Polarimetric hyperspectral imaging with acousto-optic tunable filter in the visible to shortwave infrared range

Feng Jin, Emir Haskovic, Susan Kutcher, Sudhir Trivedi, Jolanta Soos, Chein-I Chang, Bai Xue, Narasimha Prasad

Proceedings Volume 10766, 107660N (2018) https://doi.org/10.1117/12.2323554

KEYWORDS: Polarization, Polarimetry, Hyperspectral imaging, Imaging systems, Acousto-optics, Tunable filters, Infrared imaging

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Proceedings Article | 29 May 2018 Presentation + Paper

Acousto-optic tunable filter based spectrapolarimeter for extraction of Stokes and Mueller matrices

Narasimha Prasad, Feng Jin, Emir Haskovic, Susan Kutcher, Sudhir Trivedi, Jolanta Soos

Proceedings Volume 10655, 106550A (2018) https://doi.org/10.1117/12.2305265

KEYWORDS: Polarization, Polarimetry, Cameras, Imaging systems, Hyperspectral imaging, Acousto-optics, Tunable filters, Liquid crystals, Staring arrays, Mueller matrices

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Proceedings Article | 23 May 2018 Presentation + Paper

Effect of additives: Organic-metal oxide nanocomposites for γ-ray sensors

N. B. Singh, Ching Hua Su, Bradley Arnold, Fow-Sen Choa, Christopher Cooper, Stacey Sova, Puneet Gill, Vishall Dayal, Lisa Kelly, Narasimha Prasad, Paul Smith, Brian Cullum

Proceedings Volume 10629, 106290D (2018) https://doi.org/10.1117/12.2301084

KEYWORDS: Composites, Oxides, Sensors, Urea, Nickel, Metals, Nanocomposites, Crystals, Nanoparticles, Particles

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Proceedings Article | 23 February 2018 Presentation + Paper

Reliability testing of ultra-low noise InGaAs quad photoreceivers

Abhay Joshi, Shubhashish Datta, Narasimha Prasad, Michael Sivertz

Proceedings Volume 10526, 105261J (2018) https://doi.org/10.1117/12.2293010

KEYWORDS: Photodiodes, Capacitance, Indium gallium arsenide, Nanoimprint lithography, Amplifiers, Reliability, Interferometry, Signal to noise ratio, Gallium, Photography

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Proceedings Article | 23 February 2018 Paper

Optical characteristics of novel bulk and nanoengineered laser host materials

Narasimha Prasad, Stacey Sova, Lisa Kelly, Talon Bevan, Bradley Arnold, Christopher Cooper, Fow-Sen Choa, N. B. Singh

Proceedings Volume 10533, 1053320 (2018) https://doi.org/10.1117/12.2295994

KEYWORDS: Crystals, Lanthanum, Calcium, Silicates, Luminescence, Neodymium, Absorbance, Iron, Chromium, Solids

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Proceedings Article | 19 February 2018 Paper

Short pulse characterization requires recognizing inseparability of auto-correlation and spectral measurements

Chandrasekhar Roychoudhuri, Narasimha Prasad

Proceedings Volume 10522, 105221N (2018) https://doi.org/10.1117/12.2295832

KEYWORDS: Sensors, Fourier transforms, Superposition, Visibility, Pulsed laser operation, Spectroscopy, Correlation function, Michelson interferometers

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We present a mathematical approach to appreciate that short pulse characterization requires recognizing inseparability of the measurements of the amplitude envelope-correlation and spectral measurements and then use a suitable iterative approach to derive the real characteristics. We will use a standard Michelson interferometer, as usual, to introduce the autocorrelation function of a pulse containing single and multiple frequencies. In the process, we also underscore that detectors play the key role in generating measurable Superposition Effects (SE), recognized as fringes after the detectors carry out the square modulus operation. Simple mathematical summation of amplitude factors, the Superposition Principle (SP), is not directly observable. We underscore this by mentioning that we present EM waves as classical and detectors as quantum mechanical. This semi-classical approach has been established by Lamb and Jaynes, which is indirectly supported by Glauber’s comment, “A photon is what a detector detects”. The semi-classical approach helps us separate the phenomenological difference between the absorbed detected energy by a detector (SE) from the energy supplied by the simultaneously present multiple wave amplitudes (SP). As in atomic and molecular physics, we use the detector’s dipolar stimulation as the product of its linear dipolar polarizability multiplied by all the EM fields stimulating it simultaneously. The analysis also demonstrates that for a pulse containing multiple frequencies, the two-beam autocorrelation function becomes a product of the traditional amplitude correlation factor and a frequency-comb correlation factor. Hence, the spectral interpretation of a short pulse and two-beam autocorrelation are inseparable. Therefore, the detailed characterization would require iterative computational approach by guessing the most plausible functional forms. This deeper understanding can be applied to rapid re-calibration of pulsed lasers that need to be maintained at single mode but has the tendency to move to multimode behavior. If the newly measured autocorrelation function differs from the original amplitude correlation factor, then one should check for the spectral characteristics first, before assuming that only the pulse shape has changed.

SPIE Journal Paper | 19 July 2017

Nanomorphology and performance of pure and doped lead selenide for infrared detector

Narsingh Bahadur Singh, Christopher Cooper, Pietro Strobbia, Narasimha Prasad, Ching Hua Su, Bradley Arnold, Fow-Sen Choa

OE, Vol. 56, Issue 07, 077106, (July 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.7.077106

KEYWORDS: Annealing, Lead, Cadmium, Infrared detectors, Glasses, Silicon, Nanorods, Mid-IR, Tin, Scanning electron microscopy

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SPIE Journal Paper | 2 March 2017

Three-beam aerosol backscatter correlation lidar for wind profiling

Narasimha Prasad, Anand Radhakrishnan Mylapore

OE, Vol. 56, Issue 03, 031222, (March 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.3.031222

KEYWORDS: LIDAR, Aerosols, Backscatter, Transceivers, Wind measurement, Pulsed laser operation, Profiling, Sensors, Prototyping, Algorithm development

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Proceedings Article | 22 September 2016 Paper

Ultra high molecular weight polyethylene (UHMWPE) fiber epoxy composite hybridized with Gadolinium and Boron nanoparticles for radiation shielding

Venkat Mani, Narasimha Prasad, Ajit Kelkar

Proceedings Volume 9981, 99810D (2016) https://doi.org/10.1117/12.2240135

KEYWORDS: Hydrogen, Radiation effects, Nanoparticles, Gadolinium, Boron, Composites, Particles, Epoxies, Space operations, Polymers

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Deep space radiations pose a major threat to the astronauts and their spacecraft during long duration space exploration missions. The two sources of radiation that are of concern are the galactic cosmic radiation (GCR) and the short lived secondary neutron radiations that are generated as a result of fragmentation that occurs when GCR strikes target nuclei in a spacecraft. Energy loss, during the interaction of GCR and the shielding material, increases with the charge to mass ratio of the shielding material. Hydrogen with no neutron in its nucleus has the highest charge to mass ratio and is the element which is the most effective shield against GCR. Some of the polymers because of their higher hydrogen content also serve as radiation shield materials. Ultra High Molecular Weight Polyethylene (UHMWPE) fibers, apart from possessing radiation shielding properties by the virtue of the high hydrogen content, are known for extraordinary properties. An effective radiation shielding material is the one that will offer protection from GCR and impede the secondary neutron radiations resulting from the fragmentation process. Neutrons, which result from fragmentation, do not respond to the Coulombic interaction that shield against GCR. To prevent the deleterious effects of secondary neutrons, targets such as Gadolinium are required. In this paper, the radiation shielding studies that were carried out on the fabricated sandwich panels by vacuum-assisted resin transfer molding (VARTM) process are presented. VARTM is a manufacturing process used for making large composite structures by infusing resin into base materials formed with woven fabric or fiber using vacuum pressure. Using the VARTM process, the hybridization of Epoxy/UHMWPE composites with Gadolinium nanoparticles, Boron, and Boron carbide nanoparticles in the form of sandwich panels were successfully carried out. The preliminary results from neutron radiation tests show that greater than 99% shielding performance was achieved with these sandwich panels. Moreover, the mechanical testing and thermo-physical analysis performed show that core materials can preserve their thermo-physical and mechanical integrity after radiation.

Proceedings Article | 19 September 2016 Paper

Probing organic residues on Martian regolith simulants using a long-wave infrared Laser-induced breakdown spectroscopy linear array detection system

Narasimha Prasad, Clayton S.-C. Yang, Feng Jin, Ken Jia, EiEi Brown, Uwe Hömmerich, Yingqing Jia, Sudhir Trivedi, Priyalal Wijewarnasuriya, Eric Decuir, Alan Samuels

Proceedings Volume 9981, 99810I (2016) https://doi.org/10.1117/12.2242901

KEYWORDS: Laser induced breakdown spectroscopy, Long wavelength infrared, Detector arrays, Visible radiation, Infrared spectroscopy, Infrared radiation, Molecular lasers, Infrared detectors, Pulsed laser operation, Molecules

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Proceedings Article | 28 March 2016 Paper

Innovative fiber-laser architecture-based compact wind lidar

Narasimha Prasad, Allen Tracy, Steve Vetorino, Richard Higgins, Russ Sibell

Proceedings Volume 9754, 97540J (2016) https://doi.org/10.1117/12.2218226

KEYWORDS: LIDAR, Sensors, Fiber amplifiers, 3D scanning, Scanners, Wind measurement, Optical amplifiers, Fiber lasers, Signal processing, Laser scanners

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Proceedings Article | 25 September 2015 Paper

Tabletop demonstration of non-Interaction of photons and non-interference of waves

Narasimha Prasad, Chandra Roychoudhuri

Proceedings Volume 9570, 95701B (2015) https://doi.org/10.1117/12.2191014

KEYWORDS: Glasses, Photons, Scattering, Superposition, Laser scattering, Chromium, Silica, Physics, Sensors, Surface finishing

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Recently, Non- Interaction of Waves or the NIW property has been proposed as a generic property of all propagating electromagnetic waves by one of the authors (CR). In other words, optical beams do not interact with each other to modify or re-distribute their field energy distribution in the absence of interacting materials. In this paper, path taken to re-create CR's original demonstration of the NIW-property as an on-site tabletop experiment is discussed. Since 1975, when the NIW demonstration was first reported, several advances in lasers and optical component design architecture have occurred. With the goal of using low cost components and having agility in setting up on non-conformable platforms for general viewing, a compact arrangement for demonstrating the NIW property was envisioned. In our experimental arrangement, a beam multiplier element was utilized to generate a set of spatially separate parallel beams out of an incident laser beam. The emerging parallel beams from the beam multiplier element were then focused on a one-sided ground glass, the flat side being towards the beam multiplier. This flat side reflects off all the incident focused beams as fanning out independent laser beams, remaining unperturbed even though they are reflecting out of a common superposed spot. It is clear that there is neither "interference between different photons", nor "a photon interferes with itself", even within a region of superposed beams. In contrast, the ground glass surface (same silica molecules but granular or lumpy) was anticipated to generate a set of crisp spatial fringes on its surface as in the original experiment. The fringes are due to granulated individual silica lumps responding simultaneously to the local resultant E-vectors due to all the superposed beams and are scattering energy proportional to the square modulus of the sum of all the simultaneous dipolar amplitude stimulations. The dark fringe locations imply zero resultant amplitude stimulation and hence no scattering. Due to multi-longitudinal mode nature of laser module, the fringes appeared washed out at the backside of the ground glass plate. Experimental refinements followed by our views on whether the fundamental physics behind the generation of superposition fringes by photo detectors different from those due to a ground glass are briefly discussed.

Proceedings Article | 15 June 2015 Paper

An all-fiber, modular, compact wind lidar for wind sensing and wake vortex applications

Narasimha Prasad, Russel Sibell, Steven Vetorino, Richard Higgins, Allen Tracy

Proceedings Volume 9465, 94650C (2015) https://doi.org/10.1117/12.2181170

KEYWORDS: LIDAR, Sensors, Scanners, 3D scanning, Fiber amplifiers, Wind measurement, Aerosols, Laser scanners, Signal processing, Transmitters

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Proceedings Article | 18 May 2015 Paper

Inhomogeneous thermoelectric materials: improving overall zT by localized property variations

Narasimha Prasad, David Nemir, Jan Beck, Jay Maddux, Patrick Taylor

Proceedings Volume 9493, 949305 (2015) https://doi.org/10.1117/12.2181143

KEYWORDS: Thermoelectric materials, Nanostructuring, Nanostructures, Scattering, Solids, Crystals, Composites, Ranging, Nanocomposites, Phonons

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Proceedings Article | 13 May 2015 Paper

Growth and morphology of lead tin selenide for MWIR detectors

Christopher Cooper, Pietro Strobbia, Emily Schultheis, Narasimha Prasad, Bradley Arnold, Fow-Sen Choa, Narsingh Singh

Proceedings Volume 9491, 949104 (2015) https://doi.org/10.1117/12.2179724

KEYWORDS: Lead, Tin, Glasses, Silicon, Sensors, Mid-IR, Long wavelength infrared, Annealing, Thin films, Infrared detectors

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Proceedings Article | 17 October 2014 Paper

Shockwave consolidation of nanostructured thermoelectric materials

Narasimha Prasad, Patrick Taylor, David Nemir

Proceedings Volume 9226, 92260J (2014) https://doi.org/10.1117/12.2063852

KEYWORDS: Thermoelectric materials, Explosives, Nanostructuring, Bismuth, Crystals, Electroluminescence, Nanotechnology, Nanostructures, Temperature metrology, Electronic circuits

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Proceedings Article | 17 October 2014 Paper

Post-flight test results of acousto-optic modulator and acousto-optic tunable filter devices subjected to space exposure

Narasimha Prasad, Sudhir Trivedi, Jolanta Rosemeier, Mark Diestler

Proceedings Volume 9226, 922609 (2014) https://doi.org/10.1117/12.2063853

KEYWORDS: Bragg cells, Diffraction, Acousto-optics, Acoustics, LIDAR, Fiber lasers, Semiconductor lasers, Sensors, Commercial off the shelf technology, Measurement devices

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Proceedings Article | 9 June 2014 Paper

A three-beam aerosol backscatter correlation lidar for three-component wind profiling

Anand Radhakrishnan Mylapore, Geary Schwemmer, Coorg Prasad, Sangwoo Lee, Alexander Achey, In Heon Hwang, Nikhil Mehta, Mikhail Yakshin, Konstantin Novoselov, Narasimha Prasad

Proceedings Volume 9080, 90800Y (2014) https://doi.org/10.1117/12.2053066

KEYWORDS: LIDAR, Aerosols, Wind measurement, Transceivers, Backscatter, Prototyping, Spatial resolution, Turbulence, Sensors, Atmospheric particles

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Proceedings Article | 1 October 2013 Paper

Does the coherent lidar system corroborate non-interaction of waves (NIW)?

Narasimha Prasad, Chandrasekhar Roychoudhuri

Proceedings Volume 8832, 883209 (2013) https://doi.org/10.1117/12.2025459

KEYWORDS: LIDAR, Polarization, Optical components, Sensors, Wave plates, Elliptical polarization, Pulsed laser operation, Superposition, Beam splitters, Molecules

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Proceedings Article | 1 October 2013 Paper

Understanding beam alignment in a coherent lidar system

Narasimha Prasad, Chandrasekhar Roychoudhuri,

Proceedings Volume 8832, 88320A (2013) https://doi.org/10.1117/12.2025460

KEYWORDS: Sensors, LIDAR, Superposition, Heterodyning, Optical alignment, Receivers, Signal detection, Wavefronts, Signal to noise ratio, Oscillators

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Proceedings Article | 24 September 2013 Paper

Post-flight test results of seed laser module subjected to space exposure

Narasimha Prasad

Proceedings Volume 8876, 88760C (2013) https://doi.org/10.1117/12.2025461

KEYWORDS: Semiconductor lasers, LIDAR, Fiber lasers, Sensors, Diodes, Ultraviolet radiation, Space operations, Oxygen, Modulators, Environmental sensing

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Proceedings Article | 4 June 2013 Paper

Development of advanced seed laser modules for lidar and spectroscopy applications

Narasimha Prasad, Alex Rosiewicz, Steve Coleman

Proceedings Volume 8733, 873306 (2013) https://doi.org/10.1117/12.2018195

KEYWORDS: Carbon dioxide, Carbon dioxide lasers, Laser applications, Electronics, Prototyping, Spectroscopy, Oxygen, Carbon monoxide, Transmitters, LIDAR

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Proceedings Article | 31 May 2013 Paper

Comparative analysis of alternative spectral bands of CO2 and O2 for the sensing of CO2 mixing ratios

Denis Pliutau, Narasimha Prasad

Proceedings Volume 8718, 87180L (2013) https://doi.org/10.1117/12.2016337

KEYWORDS: Temperature metrology, Carbon dioxide, Oxygen, Atmospheric modeling, Absorption, Data modeling, LIDAR, Analytical research, Atmospheric sensing, Environmental sensing

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Proceedings Article | 23 May 2013 Paper

Usage of data-encoded web maps with client side color rendering for combined data access, visualization, and modeling purposes

Denis Pliutau, Narasimha Prasad

Proceedings Volume 8747, 87470K (2013) https://doi.org/10.1117/12.2016325

KEYWORDS: Data modeling, Data storage, Visualization, Visual process modeling, Data conversion, Image compression, Optical filters, Satellites, MODIS, Computer simulations

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Proceedings Article | 20 May 2013 Paper

Semi-empirical validation of the cross-band relative absorption technique for the measurement of molecular mixing ratios

Denis Pliutau, Narasimha Prasad

Proceedings Volume 8731, 87310L (2013) https://doi.org/10.1117/12.2016661

KEYWORDS: Temperature metrology, Oxygen, Absorption, Carbon dioxide, Data modeling, Molecules, LIDAR, Analytical research, Error analysis, Atmospheric sensing

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Proceedings Article | 26 February 2013 Paper

Single-frequency, single-polarization holmium-doped ZBLAN fiber laser

X. Zhu, J. Zong, A. Miller, K. Wiersma, R. Norwood, N. Prasad, A. Chavez-Pirson, N. Peyghambarian

Proceedings Volume 8601, 86010Y (2013) https://doi.org/10.1117/12.2003214

KEYWORDS: Fiber lasers, ZBLAN, Optical fibers, Fiber Bragg gratings, Glasses, Absorption, Polarization, Photonics, Cladding, Raman spectroscopy

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Proceedings Article | 24 October 2012 Paper

Simulation studies for comparative evaluation of alternative spectral regions for the sensing of CO2 and O2 suitable for the ASCENDS Mission

Denis Pliutau, Narasimha Prasad

Proceedings Volume 8513, 851309 (2012) https://doi.org/10.1117/12.933277

KEYWORDS: Carbon dioxide, Oxygen, Atmospheric modeling, Atmospheric optics, Error analysis, Molecules, Humidity, Carbon dioxide lasers, LIDAR, Data modeling

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Proceedings Article | 15 October 2012 Paper

Performance testing of lidar components subjected to exposure in space via MISSE 7 mission

Narasimha Prasad

Proceedings Volume 8519, 85190O (2012) https://doi.org/10.1117/12.933275

KEYWORDS: LIDAR, Receivers, Sensors, Photodiodes, Ultraviolet radiation, Fiber lasers, Semiconductor lasers, Diodes, Space operations, Oxygen

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Proceedings Article | 25 May 2012 Paper

Frequency up-conversion detection system for space-based lidar

Yi Jiang, Yujie Ding, Ioulia Zotova, Narasimha Prasad

Proceedings Volume 8385, 838504 (2012) https://doi.org/10.1117/12.918531

KEYWORDS: Upconversion, Crystals, Gases, Laser crystals, Nonlinear crystals, Mid-IR, Sensors, Absorption, Nd:YAG lasers, Quantum efficiency

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Proceedings Article | 25 May 2012 Paper

Development of PbTe material for advanced thermoelectric power generation

Narasimha Prasad, Sudhir Trivedi, Witold Palosz, Robert Rosemeier, Cory Rosemeier, Susan Kutcher, David Mayers, Patrick Taylor, Jay Maddux, Jogender Singh

Proceedings Volume 8377, 83770K (2012) https://doi.org/10.1117/12.920875

KEYWORDS: Crystals, Thermoelectric materials, Nanocomposites, Copper, Convection, Temperature metrology, Resistance, Composites, Interfaces, Contamination

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Proceedings Article | 24 May 2012 Paper

Low SWaP semiconductor laser transmitter modules for ASCENDS Mission applications

Narasimha Prasad, Alex Rosiewicz, Steve Coleman

Proceedings Volume 8381, 83810J (2012) https://doi.org/10.1117/12.921276

KEYWORDS: Carbon dioxide, Electronics, Carbon dioxide lasers, Semiconductor lasers, Transmitters, Oxygen, Laser development, Temperature metrology, Laser stabilization, Heterodyning

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Proceedings Article | 22 May 2012 Paper

Simulation framework to estimate the performance of CO2 and O2 sensing from space and airborne platforms for the ASCENDS mission requirements analysis

Denis Pliutau, Narasimha Prasad

Proceedings Volume 8379, 83790K (2012) https://doi.org/10.1117/12.919476

KEYWORDS: Atmospheric modeling, Carbon dioxide, Error analysis, Data modeling, LIDAR, Oxygen, Atmospheric optics, Molecules, 3D modeling, Databases

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Proceedings Article | 16 February 2012 Paper

Holmium-doped ZBLAN fiber lasers at 1.2 µm

X. Zhu, J. Zong, R. Norwood, A. Chavez-Person, N. Peyghambarian, N. Prasad

Proceedings Volume 8237, 823727 (2012) https://doi.org/10.1117/12.906795

KEYWORDS: ZBLAN, Fiber lasers, Glasses, Absorption, Luminescence, Holmium, Fiber amplifiers, Ions, Raman spectroscopy, Optical fibers

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Proceedings Article | 7 February 2012 Paper

Discerning comb and Fourier mean frequency from an fs laser based on the principle of non-interaction of waves

Chandrasekhar Roychoudhuri, Narasimha Prasad

Proceedings Volume 8236, 82360G (2012) https://doi.org/10.1117/12.906493

KEYWORDS: Spectroscopy, Mode locking, Sensors, Frequency combs, Superposition, Chemical species, Wave propagation, Molecules, Femtosecond phenomena, Visualization

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The key objective of this article is to underscore that as engineers, we need to pay close attention in repeatedly validating and re-validating the underlying physical processes behind a working theory that models a phenomenon we are using to create tools and technologies. We use the test case, the prevailing mode-lock theory, to illustrate our views by identifying existing contradictions and showing approach towards their resolution by identifying the relevant physical processes. The current theory tells us that the Fourier summation of all the allowed cavity modes directly produces the train of pulses. It effectively assumes that electromagnetic (EM) waves are capable of re-organizing their spatial and temporal energy distribution to generate a train of temporal pulses while preserving the spatial mode energy distribution. The implication is that EM waves interact with each other by themselves. Even though the theory is working, we have three logical problems. First, in the real world, in the linear domain, waves never interact with each other. On careful analysis of all types of interference experiments, we will recognize that only in the presence of some interacting material medium can we observe the physical superposition EFFECT. In other words, detectors carryout the superposition effect we call interference phenomenon, through the summation of their multiple simultaneous linear stimulations and then absorbing energy proportional to the square modulus of the sum total stimulation. Second, a Fourier monochromatic wave, existing in all space and time, is a non-causal hypothesis. Just because our theories are working does not mean that we have understood the real physical interaction processes in nature. We need to build our theories based upon space and time finite EM wave packet containing a finite amount of energy, which is a causal approach. Third, in spite of staggering successes of Quantum Mechanics, we do not yet have a self consistent model for space and time finite model of a photon. QM only predicts that EM energy emission (spontaneous and stimulated) takes place only in a discrete amount at a time from atoms and molecules. It does not give us recipe about how to visualize a propagating photon as it expands diffractively. However, Huygens-Fresnel's classical diffraction integral gives us a rigorous model, which is the cornerstone of modeling evolution of laser cavity modes, CW or pulsed. In this paper, we highlight the contradictions that arise out of the prevailing mode-lock theory and resolve them by using causal models, already underscored above. For example, there are now a wide range of very successful technological applications of the frequency comb extracted out of fs lasers. If the Fourier summation were the correct physical process, then all the cavity modes would have been summed (converted) into a single mean frequency around the gain line center for perfectly mode-locked systems. Further, sending such fs pulses through an optical spectrometer would have always displayed a transform limited fringe, centering on the mean Fourier frequency, rather than generating the comb frequencies, albeit instrumentally broadened. Output pulse train from a phase locked laser is functionally produced due to the oscillatory time-gating behavior of the intra-cavity phase-locking devices. So, we need to pay more attention to the fast temporal behavior of the materials we use for achieving very fast time-gating, since this material imposes phase locking on the cavity modes to enhance its own high-contrast time-gating behavior.

SPIE Journal Paper | 1 December 2011

Pseudorandom noise code-based technique for thin-cloud discrimination with CO₂ and O₂absorption measurements

Joel Campbell, Narasimha Prasad, Michael Flood

OE, Vol. 50, Issue 12, 126002, (December 2011) https://doi.org/10.1117/12.10.1117/1.3658758

KEYWORDS: Signal to noise ratio, Tin, Absorption, Clouds, Modulation, LIDAR, Carbon monoxide, Continuous wave operation, Interference (communication), Aerosols

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Proceedings Article | 29 September 2011 Paper

Appreciating the principle of Non-Interaction of Waves (NIW-principle) by modeling Talbot diffraction patterns at different planes

Narasimha Prasad, Chandra Roychoudhuri

Proceedings Volume 8121, 81211B (2011) https://doi.org/10.1117/12.894044

KEYWORDS: Diffraction, Wavelets, Sensors, Diffraction gratings, Near field, Wave propagation, MATLAB, Ray tracing, Fringe analysis, Superposition

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Proceedings Article | 29 September 2011 Paper

Microscope and spectroscope results are not limited by Heisenberg's Uncertainty Principle!

Narasimha Prasad, Chandrasekhar Roychoudhuri

Proceedings Volume 8121, 81210F (2011) https://doi.org/10.1117/12.895207

KEYWORDS: Spectroscopy, Microscopes, Spectral resolution, Chemical species, Super resolution, Time-frequency analysis, Integration, Iron, Spectroscopes

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Proceedings Article | 29 September 2011 Paper

Visualizing the mode evolution process in passive and active cavities based on the NIW-Principle

Narasimha Prasad, Chandrasekhar Roychoudhuri

Proceedings Volume 8121, 81211D (2011) https://doi.org/10.1117/12.895167

KEYWORDS: Wave propagation, Visualization, Wavelets, Signal processing, Beam propagation method, Diffraction, Mirrors, Mode locking, MATLAB, Computer simulations

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Proceedings Article | 22 September 2011 Paper

Recent progress made in testing laser diodes and optical materials subjected to exposure in space

Narasimha Prasad

Proceedings Volume 8164, 816402 (2011) https://doi.org/10.1117/12.895411

KEYWORDS: Semiconductor lasers, Waveguide lasers, Ultraviolet radiation, Diodes, Optical components, Contamination, Fiber lasers, Space operations, Oxygen, LIDAR

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Proceedings Article | 9 June 2011 Paper

Pseudorandom noise code-based technique for cloud and aerosol discrimination applications

Joel Campbell, Narasimha Prasad, Michael Flood, Wallace Harrison

Proceedings Volume 8037, 80370L (2011) https://doi.org/10.1117/12.888132

KEYWORDS: Signal to noise ratio, Carbon dioxide, Clouds, Aerosols, Continuous wave operation, Carbon dioxide lasers, Absorption, Interference (communication), LIDAR, Signal processing

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Proceedings Article | 24 March 2011 Paper

Development of a low SWaP laser transmitter for atmospheric lidar applications

Narasimha Prasad, Alex Rosiewicz, Steven Coleman

Proceedings Volume 7912, 791206 (2011) https://doi.org/10.1117/12.878856

KEYWORDS: Carbon dioxide, Carbon dioxide lasers, Transmitters, Oxygen, Laser applications, Prototyping, Electronics, Carbon monoxide, Temperature metrology, Laser development

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Proceedings Article | 23 September 2010 Paper

Testing of laser components subjected to exposure in space

Narasimha Prasad

Proceedings Volume 7817, 781705 (2010) https://doi.org/10.1117/12.862850

KEYWORDS: Ultraviolet radiation, Radiation effects, Laser components, Semiconductor lasers, Fiber lasers, Space operations, Optical components, LIDAR, Tunable lasers, Sensors

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Proceedings Article | 15 September 2010 Paper

Recent progress on radiation detection from near-infrared to mid-infrared based on frequency upconversion

Yi Jiang, Yujie Ding, Ioulia Zotova, Narasimha Prasad

Proceedings Volume 7817, 78170B (2010) https://doi.org/10.1117/12.861949

KEYWORDS: Upconversion, Crystals, Gases, Laser crystals, Nonlinear crystals, Mid-IR, Absorption, Nd:YAG lasers, Quantum efficiency, Sensors

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Proceedings Article | 28 August 2010 Paper

New technology for microfabrication and testing of a thermoelectric device for generating mobile electrical power

Narasimha Prasad, Patrick Taylor, Sudhir Trivedi, Susan Kutcher

Proceedings Volume 7764, 776409 (2010) https://doi.org/10.1117/12.862849

KEYWORDS: Thermoelectric materials, Nanolithography, Bismuth, Crystals, Nanostructuring, Resistance, Doping, Microfabrication, Mobile devices

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Proceedings Article | 3 March 2010 Paper

Time-gating processes in intra-cavity mode-locking devices like saturable absorbers and Kerr cells

Narasimha Prasad, Chandrasekhar Roychoudhuri

Proceedings Volume 7578, 75781C (2010) https://doi.org/10.1117/12.846584

KEYWORDS: Mode locking, Wave propagation, Photons, Pulsed laser operation, Sensors, Q switches, Helium neon lasers, Superposition, Modes of laser operation, Light-matter interactions

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Proceedings Article | 10 September 2009 Paper

Exploring divisibility and summability of 'photon' wave packets in nonlinear optical phenomena

Narasimha Prasad, Chandrasekhar Roychoudhuri

Proceedings Volume 7421, 74210A (2009) https://doi.org/10.1117/12.828557

KEYWORDS: Crystals, Nonlinear optics, Nonlinear crystals, Dielectric polarization, Radio propagation, Light-matter interactions, Nonlinear dynamics, Polarization, Dispersion, Phase matching

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Proceedings Article | 9 September 2009 Paper

Testing of NASA LaRC materials under MISSE 6 and MISSE 7 missions

Narasimha Prasad

Proceedings Volume 7467, 74670E (2009) https://doi.org/10.1117/12.828554

KEYWORDS: Semiconductor lasers, Ultraviolet radiation, Optical components, LIDAR, Space operations, Sensors, Ceramics, Radiation effects, Waveguide lasers, Fiber lasers

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Proceedings Article | 28 February 2009 Paper

Development of ceramic solid state laser host materials

Narasimha Prasad, Sudhir Trivedi, Susan Kutcher, Chen-Chia Wang, Joo-Soo Kim, Uwe Hommerich, Vijay Shukla, Rajendra Sadangi

Proceedings Volume 7193, 71931X (2009) https://doi.org/10.1117/12.813785

KEYWORDS: Ceramics, Neodymium, Oxides, Crystals, Erbium, Ytterbium, Scandium, Doping, Solid state lasers, Absorption

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Proceedings Article | 28 February 2009 Paper

Some activities of MISSE 6 Mission

Narasimha Prasad

Proceedings Volume 7193, 719304 (2009) https://doi.org/10.1117/12.814870

KEYWORDS: Semiconductor lasers, Ultraviolet radiation, Optical components, Sensors, Space operations, Laser applications, Ceramics, Waveguide lasers, Laser optics, Chemical elements

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Proceedings Article | 28 February 2009 Paper

Light-matter interaction processes behind intracavity mode-locking devices

Chandrasekhar Roychoudhuri, Narasimha Prasad

Proceedings Volume 7193, 71931Q (2009) https://doi.org/10.1117/12.814868

KEYWORDS: Mode locking, Superposition, Continuous wave operation, Sensors, Spectrometers, Light-matter interactions, Pulsed laser operation, Time-frequency analysis, Fermium

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Proceedings Article | 26 August 2008 Paper

MISSE 6: testing materials in space

Narasimha Prasad, William Kinnard

Proceedings Volume 7095, 70950D (2008) https://doi.org/10.1117/12.796811

KEYWORDS: Ultraviolet radiation, Semiconductor lasers, Optical components, Sensors, Space operations, Waveguide lasers, Laser optics, Chemical elements, Ceramics, Laser applications

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Proceedings Article | 26 September 2007 Paper

Space qualification issues in acousto-optic and electro-optic devices

Narasimha Prasad, Edward Taylor, Sudhir Trivedi, Sue Kutcher, Jolanta Soos

Proceedings Volume 6713, 67130F (2007) https://doi.org/10.1117/12.737086

KEYWORDS: Adaptive optics, Acousto-optics, Space operations, Gamma radiation, Electrons, Electro optics, Crystals, Modulators, Polarization, Diffraction

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Proceedings Article | 31 August 2007 Paper

Can the 'photon interferes only with itself' hypothesis be reconciled with superposition of light from multiple beams or sources?

Chandrasekhar Roychoudhuri, Narasimha Prasad, Qing Peng

Proceedings Volume 6664, 66640S (2007) https://doi.org/10.1117/12.734363

KEYWORDS: Superposition, Sensors, Logic, Classical physics, Diffraction, Elementary particles, Heterodyning, Chemical species, Quantum mechanics, Quantum physics

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Proceedings Article | 19 May 2006 Paper

High energy single-mode all-solid-state, tunable UV laser transmitter

Narasimha Prasad, Upendra Singh, Floyd Hovis, Darrell Armstrong

Proceedings Volume 6214, 62140T (2006) https://doi.org/10.1117/12.666879

KEYWORDS: Optical amplifiers, Ultraviolet radiation, Optical parametric oscillators, Diodes, Nd:YAG lasers, Amplifiers, Oscillators, Crystals, Wind energy, Ferroelectric materials

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Proceedings Article | 28 February 2006 Paper

Development of solid-state ceramic laser material using Nd:yttria

Narasimha Prasad, Sudhir Trivedi, Susan Kutcher, Chen-Chia Wang, G. Jagannathan, Uwe Hommerich, Vijay Shukla, Rajendra Sadangi, Bernard Kear

Proceedings Volume 6100, 610012 (2006) https://doi.org/10.1117/12.657763

KEYWORDS: Ceramics, Neodymium, Crystals, Laser crystals, Solid state lasers, Annealing, Materials processing, Laser development, Plasma, Doping

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Proceedings Article | 28 February 2006 Paper

Space qualification issues in acousto optic tunable filter (AOTF) based spectrometers

Sudhir Trivedi, Jolanta Rosemeier, Feng Jin, Susan Kutcher, Ruijin Chen, Narasimha Prasad

Proceedings Volume 6100, 61001W (2006) https://doi.org/10.1117/12.659746

KEYWORDS: Transducers, Acousto-optics, Crystals, Spectrometers, Acoustics, Adaptive optics, Diffraction, Space operations, Tunable filters, Interfaces

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Proceedings Article | 13 September 2005 Paper

Self-passive Q-switching of a Nd:YAG laser

Narashima Prasad, Sudhir Triedi

Proceedings Volume 5887, 58870S (2005) https://doi.org/10.1117/12.620584

KEYWORDS: Q switches, Nd:YAG lasers, Chromium, Crystals, YAG lasers, Annealing, Ions, Laser resonators, LIDAR, Transmitters

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Proceedings Article | 13 September 2005 Paper

Sensing of kerogens and lignens using laser-induced fluorescence at deep-UV wavelengths

Narasimha Prasad, Richard Davis, Upendra Singh

Proceedings Volume 5887, 58870R (2005) https://doi.org/10.1117/12.621257

KEYWORDS: Ultraviolet radiation, Laser induced fluorescence, Luminescence, Raman spectroscopy, Deep ultraviolet, Absorption, Mars, Transmitters, Molecules, Solar system

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Proceedings Article | 13 September 2005 Paper

Development of solid state laser material using ceramic yttria

Narasimha Prasad, Sudhir Trivedi, Susan Kutcher, Chen-Chia Wang, G. Jagannathan, Uwe Hommerich, Vijay Shukla, Rajendra Sadangi, Bernard Kear

Proceedings Volume 5887, 588717 (2005) https://doi.org/10.1117/12.623912

KEYWORDS: Ceramics, Neodymium, Solid state lasers, Crystals, Laser crystals, Laser development, Diode pumped solid state lasers, Plasma, Doping, Disk lasers

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Proceedings Article | 19 August 2005 Paper

Wet/dry film thickness measurement of paint by absorption spectroscopy with acousto-optic tunable filter spectrometer

Pranay Sinha, Xiangchun Xiong, Feng Jin, Sudhir Trivedi, Narashima Prasad

Proceedings Volume 5880, 58800I (2005) https://doi.org/10.1117/12.617312

KEYWORDS: Spectroscopy, Tunable filters, Acoustics, Sensors, Acousto-optics, Absorption, Near infrared, Transducers, Coating, Absorption spectroscopy

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Proceedings Article | 27 April 2005 Paper

Novel non-stoichiometric Co²⁺: spinel passive Q-switch

Jennifer Stone-Sundberg, Milan Kokta, Narasimha Prasad, Ramesh Shori

Proceedings Volume 5707, (2005) https://doi.org/10.1117/12.623235

KEYWORDS: Spinel, Crystals, Cobalt, Q switching, Q switches, Absorption, Q switched lasers, Laser applications, Magnesium, YAG lasers

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Proceedings Article | 20 October 2004 Paper

Angle-discrimination-based pointing and tracking for free-space communication links

Narasimha Prasad, Patrick Kratovil, Charles Bjork, Neil Vallestero

Proceedings Volume 5550, (2004) https://doi.org/10.1117/12.562084

KEYWORDS: Receivers, Sensors, Transmitters, Scintillation, Scanners, Modulation, Telecommunications, Transponders, Data acquisition, Global Positioning System

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Proceedings Article | 8 July 2004 Paper

Passively Q-switched eyesafe Yb:Er:glass laser

Narasimha Prasad, Chris Urbina, Bradford Tousley, Ramesh Shori, Jennifer Stone-Sundberg, Milan Kokta

Proceedings Volume 5332, (2004) https://doi.org/10.1117/12.538042

KEYWORDS: Semiconductor lasers, Resonators, Diodes, Pulsed laser operation, Ytterbium, Q switched lasers, Doping, Erbium, Fiber lasers, Q switching

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Proceedings Article | 27 February 2004 Paper

Acousto-optic tunable filter-based active long-wave IR spectrapolarimetric imager

Narasimha Prasad

Proceedings Volume 5268, (2004) https://doi.org/10.1117/12.519646

KEYWORDS: Optical parametric oscillators, Long wavelength infrared, Imaging systems, Acousto-optics, Crystals, Mercury, Chlorine, Polarization, Tunable filters, Acoustics

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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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Proceedings Article | 27 January 2004 Paper

Free-space optical communication link performance enhancement via modified receiver geometric characteristics

Narasimha Prasad, Patrick Kratovil, Sara Tucker, Neil Vallestero, Mark Khusid

Proceedings Volume 5160, (2004) https://doi.org/10.1117/12.510630

KEYWORDS: Receivers, Scintillation, Sensors, Signal to noise ratio, Signal detection, Turbulence, Free space optical communications, Transmitters, Refractive index, Atmospheric turbulence

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Proceedings Article | 9 December 2002 Paper

Free-space optical communication systems (FOCUS): an Army overview

Neil Vallestero, Mark Khusid, Narasimha Prasad, John Carrano, George Duchak, Jennifer Ricklin, Mikhail Vorontsov

Proceedings Volume 4821, (2002) https://doi.org/10.1117/12.450522

KEYWORDS: Telecommunications, Laser communications, Laser systems engineering, Data communications, Data modeling, Systems modeling, Performance modeling, Atmospheric modeling, Free space optical communications, Video

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Proceedings Article | 9 December 2002 Paper

Data communication in mid-IR using a solid state laser-pumped optical parametric oscillator

Narasimha Prasad, Duane Smith, James Magee

Proceedings Volume 4821, (2002) https://doi.org/10.1117/12.453549

KEYWORDS: Mid-IR, Weapons, Fiber optic gyroscopes, Optical parametric oscillators, Transmitters, Fourier transforms, Transceivers, Atmospheric modeling, Image transmission, Forward looking infrared

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Proceedings Article | 4 June 2002 Paper

High-damage threshold rectangular hollow waveguides for directed energy applications

Narasimha Prasad, D. Smith, James Magee

Proceedings Volume 4632, (2002) https://doi.org/10.1117/12.469771

KEYWORDS: Hollow waveguides, Directed energy weapons, Waveguides, Medium wave, Laser damage threshold, Beam controllers, Palladium, Silver, High power lasers, Electro optical sensors

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Proceedings Article | 26 April 2002 Paper

Image transmission in mid-IR using a solid state laser pumped optical parametric oscillator

Narasimha Prasad, Pat Kratovil, James Magee

Proceedings Volume 4635, (2002) https://doi.org/10.1117/12.464102

KEYWORDS: Mid-IR, Image transmission, Pulsed laser operation, Optical parametric oscillators, Electronics, Transmitters, Transceivers, Weapons, Q switched lasers, Semiconductor lasers

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Proceedings Article | 28 October 1996 Paper

Optical alignment monitoring and stabilization using a liquid crystal television (LCTV)

Narasimha Prasad, Sean Doyle, Michael Giles

Proceedings Volume 2810, (1996) https://doi.org/10.1117/12.255134

KEYWORDS: Point spread functions, Optical alignment, Liquid crystals, Televisions, Phase shift keying, Video, Polarization, Software, Telecommunications, Phase modulation

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SPIE Journal Paper | 1 July 1996

Collimation and beam alignment: testing and estimation using liquid-crystal televisions

Narasimha Prasad, Sean Doyle, Michael Giles

OE, Vol. 35, Issue 07, (July 1996) https://doi.org/10.1117/12.10.1117/1.600771

KEYWORDS: Collimation, Point spread functions, Liquid crystals, Televisions, Optical alignment, Analytical research, Video, CCD cameras, Phase shift keying, Charge-coupled devices

Proceedings Article | 26 June 1996 Paper

Semiconductor diode-pumped optical parameter oscillator and amplifier-based compact range finder

Narasimha Prasad, Allen Geiger, Richard Richmond

Proceedings Volume 2748, (1996) https://doi.org/10.1117/12.243568

KEYWORDS: Diodes, Semiconductor lasers, Optical parametric oscillators, Crystals, Capacitors, Power supplies, Pulsed laser operation, Electronics, Semiconductors, LIDAR

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Proceedings Article | 14 June 1996 Paper

Fuzzy-logic-based approach to color quality processing

Nadipuram Prasad, Narasimha Prasad

Proceedings Volume 2761, (1996) https://doi.org/10.1117/12.243244

KEYWORDS: Fuzzy logic, Visualization, Surface plasmons, Reflectivity, Spectrophotometry, Visual analytics, Statistical analysis, Error analysis, Data processing, Inspection

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Proceedings Article | 14 June 1996 Paper

Fuzzy-logic-based cooling scheme for laser materials

Narasimha Prasad, Nadipuram Prasad

Proceedings Volume 2755, (1996) https://doi.org/10.1117/12.243177

KEYWORDS: Fuzzy logic, Crystals, Thermoelectric materials, Temperature metrology, Device simulation, Process control, Lanthanum, Thermal effects, Solid state lasers, Semiconductors

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Proceedings Article | 14 June 1996 Paper

Optical information processing system for aiding the diagnosis of pulmonary embolism

Natalie Clark, Narasimha Prasad, Michele Banish, Frederick Datz, Paul Christian

Proceedings Volume 2749, (1996) https://doi.org/10.1117/12.243105

KEYWORDS: Diffraction gratings, Diagnostics, Optical signal processing, Image processing, Visualization, Multiplexing, Lung, Polarizers, Binary data, Nuclear medicine

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Proceedings Article | 7 June 1996 Paper

Advanced systems for parametric imaging in the mid-IR region

Narasimha Prasad, Allen Geiger

Proceedings Volume 2739, (1996) https://doi.org/10.1117/12.241933

KEYWORDS: Crystals, Optical parametric oscillators, Diodes, Laser crystals, Imaging systems, Nonlinear crystals, Semiconductor lasers, Crystal optics, Semiconductors, Mid-IR

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SPIE Journal Paper | 1 April 1996

Remote sensing of propane and methane by means of a differential absorption lidar by topographic reflection

Narasimha Prasad, Allen Geiger

OE, Vol. 35, Issue 04, (April 1996) https://doi.org/10.1117/12.10.1117/1.600599

KEYWORDS: Optical parametric oscillators, Absorption, LIDAR, Methane, Crystals, Remote sensing, Signal processing, Signal attenuation, Sensors, Atmospheric sensing

Proceedings Article | 13 October 1995 Open Access

Liquid crystal television (LCTV) as an optics education tool

Michael Giles, Narasimha Prasad, Sean Doyle

Proceedings Volume 2525, (1995) https://doi.org/10.1117/12.224058

KEYWORDS: Optical components, Liquid crystals, Polarization, Point spread functions, Polarizers, Monochromatic aberrations, Diffraction, Binary data, Fresnel lenses, Televisions

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Proceedings Article | 23 August 1995 Paper

Liquid crystal television (LCTV) as an angle-tuning means for phase matching in three-wave mixing devices

Narasimha Prasad, Natalie Clark

Proceedings Volume 2566, (1995) https://doi.org/10.1117/12.217383

KEYWORDS: Binary data, Optical parametric oscillators, Crystals, Liquid crystals, Spherical lenses, Polarization, Point spread functions, Wavelength tuning, Mirrors, Phase matching

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Proceedings Article | 11 August 1995 Paper

Programmable deflector and scanner using a liquid crystal television (LCTV)

Narasimha Prasad, Sean Doyle, Michael Giles

Proceedings Volume 2537, (1995) https://doi.org/10.1117/12.216400

KEYWORDS: Point spread functions, Liquid crystals, Scanners, Fresnel lenses, Wavefronts, Video, Televisions, Electronics, Acousto-optics, Polarization

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Proceedings Article | 5 July 1995 Paper

Laser-beam diagnostics using fuzzy logic

Narasimha Prasad, Nadipuram Prasad

Proceedings Volume 2484, (1995) https://doi.org/10.1117/12.213018

KEYWORDS: Resonators, Mirrors, Fuzzy logic, Device simulation, Optical simulations, Diagnostics, Laser beam diagnostics, Control systems, Switches, Optical testing

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Proceedings Article | 5 July 1995 Paper

Simulation study of a fuzzy-logic-based controller for laser cavities

Nadipuram Prasad, Narasimha Prasad

Proceedings Volume 2484, (1995) https://doi.org/10.1117/12.213017

KEYWORDS: Mirrors, Fuzzy logic, Device simulation, Resonators, Control systems, Optical simulations, Laser resonators, Laser phosphor displays, Content addressable memory, Palladium

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Proceedings Article | 10 June 1994 Paper

Fuzzy-logic-based controller for optical resonators

Nadipuram Prasad, Narasimha Prasad

Proceedings Volume 2232, (1994) https://doi.org/10.1117/12.177747

KEYWORDS: Optical resonators, Tolerancing

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Proceedings Article | 10 June 1994 Paper

Analysis of acousto-optic devices for angle tuning of optical parametric oscillators

Narasimha Prasad, Nadipuram Prasad

Proceedings Volume 2232, (1994) https://doi.org/10.1117/12.177748

KEYWORDS: Optical parametric oscillators, Acousto-optics, Bragg cells

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Showing 5 of 101 publications

Proceedings Volume Editor (4)

SPIE Conference Volume | 20 October 2015

Nanophotonics and Macrophotonics for Space Environments IX

SPIE Conference Volume | 15 October 2014

Nanophotonics and Macrophotonics for Space Environments VIII

SPIE Conference Volume | 14 October 2013

Nanophotonics and Macrophotonics for Space Environments VII

SPIE Conference Volume | 12 October 2012

Nanophotonics and Macrophotonics for Space Environments VI

Conference Committee Involvement (51)

Solid State Lasers XXXIV: Technology and Devices

25 January 2025 | San Francisco, California, United States

Quantum Sensing and Nano Electronics and Photonics XXI

25 January 2025 | San Francisco, California, United States

Quantum Sensing and Nano Electronics and Photonics XX

28 January 2024 | San Francisco, California, United States

Solid State Lasers XXXIII: Technology and Devices

28 January 2024 | San Francisco, California, United States

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems IV

21 August 2023 | San Diego, California, United States

Solid State Lasers XXXII: Technology and Devices

31 January 2023 | San Francisco, California, United States

Quantum Sensing and Nano Electronics and Photonics XIX

29 January 2023 | San Francisco, California, United States

Solid State Lasers XXXI: Technology and Devices

25 January 2022 | San Francisco, California, United States

Quantum Sensing and Nano Electronics and Photonics XVIII

24 January 2022 | San Francisco, California, United States

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems III

4 August 2021 | San Diego, California, United States

Solid State Lasers XXX: Technology and Devices

6 March 2021 | Online Only, California, United States

Solid State Lasers XXIX: Technology and Devices

4 February 2020 | San Francisco, California, United States

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems II

12 August 2019 | San Diego, California, United States

Solid State Lasers XXVIII: Technology and Devices

5 February 2019 | San Francisco, California, United States

Solid State Lasers XXVII: Technology and Devices

29 January 2018 | San Francisco, California, United States

Quantum Sensing and Nano Electronics and Photonics XV

28 January 2018 | San Francisco, California, United States

Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems

8 August 2017 | San Diego, California, United States

Solid State Lasers XXVI: Technology and Devices

30 January 2017 | San Francisco, California, United States

Quantum Sensing and Nano Electronics and Photonics XIV

29 January 2017 | San Francisco, California, United States

Planetary Defense and Space Environment Applications

30 August 2016 | San Diego, California, United States

Solid State Lasers XXV: Technology and Devices

15 February 2016 | San Francisco, California, United States

Nanophotonics and Macrophotonics for Space Environments IX

14 August 2015 | San Diego, California, United States

The Nature of Light: What are Photons? VI

10 August 2015 | San Diego, California, United States

Solid State Lasers XXIV: Technology and Devices

8 February 2015 | San Francisco, California, United States

Nanophotonics and Macrophotonics for Space Environments VIII

18 August 2014 | San Diego, California, United States

Solid State Lasers XXIII: Technology and Devices

2 February 2014 | San Francisco, California, United States

The Nature of Light: What are Photons? V

26 August 2013 | San Diego, California, United States

Nanophotonics and Macrophotonics for Space Environments VII

25 August 2013 | San Diego, California, United States

Solid State Lasers XXII: Technology and Devices

3 February 2013 | San Francisco, California, United States

Nanophotonics and Macrophotonics for Space Environments VI

13 August 2012 | San Diego, California, United States

Solid State Lasers XXI: Technology and Devices

22 January 2012 | San Francisco, California, United States

The Nature of Light: What are Photons? IV

22 August 2011 | San Diego, California, United States

Nanophotonics and Macrophotonics for Space Environments V

22 August 2011 | San Diego, California, United States

Solid State Lasers XX: Technology and Devices

23 January 2011 | San Francisco, California, United States

Nanophotonics and Macrophotonics for Space Environments IV

3 August 2010 | San Diego, California, United States

Free-Space Laser Communications X

2 August 2010 | San Diego, California, United States

Solid State Lasers XIX: Technology and Devices

24 January 2010 | San Francisco, California, United States

The Nature of Light: What are Photons? III

3 August 2009 | San Diego, California, United States

Nanophotonics and Macrophotonics for Space Environments III

3 August 2009 | San Diego, California, United States

Free-Space Laser Communications IX

2 August 2009 | San Diego, California, United States

Solid State Lasers XVIII: Technology and Devices

25 January 2009 | San Jose, California, United States

Nanophotonics and Macrophotonics for Space Environments II

11 August 2008 | San Diego, California, United States

Free-Space Laser Communications VIII

10 August 2008 | San Diego, California, United States

Solid State Lasers XVII: Technology and Devices

20 January 2008 | San Jose, California, United States

Free-Space Laser Communications VII

28 August 2007 | San Diego, California, United States

Nanophotonics and Macrophotonics for Space Environments

27 August 2007 | San Diego, California, United States

The Nature of Light: What are photons?

26 August 2007 | San Diego, California, United States

Solid State Lasers XVI: Technology and Devices

22 January 2007 | San Jose, California, United States

Solid State Lasers XV: Technology and Devices

23 January 2006 | San Jose, California, United States

Lidar Remote Sensing for Environmental Monitoring VI

2 August 2005 | San Diego, California, United States

Solid State Lasers XIV: Technology and Devices

24 January 2005 | San Jose, California, United States

Showing 5 of 51 Conference Committees

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