Dr. Thomas J. Karr Profile

Dr. Thomas J. Karr

Chief Scientist for Sensors and Directed Energy

SPIE Involvement:

Conference Program Committee | Author | Editor

Area of Expertise:

Remote Sensing , Optical Communications , Active EO Sensors , Quantum Information , Laser Radar , Space Astronomy

30 years' experience in applied physics R&D
12 years as a scientist and manager at Lawrence Livermore National Lab
Advisor to DARPA
Founder of a commercial remote sensing company
Executive Director of a satellite communications company
Many scientific publications in refereed journals
Former editor of the journal Applied Optics

Proceedings Article | 14 May 2018 Paper

Propagation of infrared ultrashort pulses in the air

Thomas Karr, Larry Stotts, Jason Schmidt, Jason Tellez, Justin Mansell

Proceedings Volume 10684, 1068414 (2018) https://doi.org/10.1117/12.2318224

KEYWORDS: Atmospheric propagation, Turbulence, Kerr effect, Ultrafast phenomena, Mid-IR, Transmitters, Infrared radiation, Short wave infrared radiation, Plasma, Dispersion

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Proceedings Article | 31 October 2014 Paper

The future dynamic world model

Thomas Karr

Proceedings Volume 9254, 92540R (2014) https://doi.org/10.1117/12.2073794

KEYWORDS: Sensors, Data modeling, Defense and security, Systems modeling, Sensing systems, Compressed sensing, Satellites, Defense technologies, Situational awareness sensors, 3D surface sensing

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SPIE Journal Paper | 1 January 2008

Operational characteristics of a long-wavelength IR multispectral imager based on an acousto-optic tunable filter

Narsingh Singh, David Kahler, David Knuteson, M. Gottlieb, D. Suhre, Andre Berghmans, Brian Wagner, Jerry Hedrick, Thomas Karr, Jack Hawkins

OE, Vol. 47, Issue 01, 013201, (January 2008) https://doi.org/10.1117/12.10.1117/1.2829768

KEYWORDS: Crystals, Long wavelength infrared, Imaging systems, Acousto-optics, Thallium, Transducers, Cameras, Mercury, Acoustics, Infrared imaging

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Proceedings Article | 26 September 2007 Paper

Phase and frequency stability for synthetic aperture LADAR

Thomas Karr, John Glezen, Henry Lee

Proceedings Volume 6712, 671202 (2007) https://doi.org/10.1117/12.729482

KEYWORDS: LIDAR, Oscillators, Fourier transforms, Image resolution, Synthetic aperture radar, Sensors, Imaging systems, Phase measurement, Chromium, Image quality

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Proceedings Article | 26 September 2007 Paper

Signal-to-noise ratios of coherent imaging LADAR

Thomas Karr

Proceedings Volume 6712, 671203 (2007) https://doi.org/10.1117/12.729491

KEYWORDS: Signal to noise ratio, LIDAR, Radar, Interference (communication), Speckle, Coherence imaging, Synthetic aperture radar, Target detection, Imaging systems, Signal analyzers

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Proceedings Article | 26 April 2007 Paper

Operational characteristics of LWIR AOTF based multispectral imager

N. Singh, M. Gottlieb, D. Suhre, D. Kahler, D. Knuteson, A. Berghmans, B. Wagner, J. Hedrick, T. Karr, J. Hawkins

Proceedings Volume 6554, 65540E (2007) https://doi.org/10.1117/12.721516

KEYWORDS: Crystals, Long wavelength infrared, Transducers, Imaging systems, Acousto-optics, Thallium, Cameras, Acoustics, Microbolometers, Gas lasers

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Proceedings Article | 10 November 2003 Paper

Synthetic aperture ladar for planetary sensing

Thomas Karr

Proceedings Volume 5151, (2003) https://doi.org/10.1117/12.505723

KEYWORDS: Sensors, Synthetic aperture radar, Image resolution, LIDAR, Receivers, Phase measurement, Imaging systems, Planets, Microwave radiation, Heterodyning

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Proceedings Article | 30 April 2003 Paper

Synthetic aperture ladar resolution through turbulence

Thomas Karr

Proceedings Volume 4976, (2003) https://doi.org/10.1117/12.479209

KEYWORDS: Turbulence, Image resolution, Transmitters, Point spread functions, Modulation transfer functions, Receivers, Video, Wave propagation, LIDAR, Atmospheric propagation

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Proceedings Article | 1 May 1990 Paper

Instabilities of atmospheric laser propagation

Thomas Karr

Proceedings Volume 1221, (1990) https://doi.org/10.1117/12.18327

KEYWORDS: Atmospheric propagation, Thermal blooming, Laser beam propagation, Earth's atmosphere, Turbulence, Wave propagation, Deformable mirrors, Computer simulations, Rayleigh scattering, Adaptive optics

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Proceedings Article | 1 May 1990 Paper

Turbulent mixing effects in models of thermal blooming

David Chambers, James Viecelli, Thomas Karr

Proceedings Volume 1221, (1990) https://doi.org/10.1117/12.18344

KEYWORDS: Atmospheric propagation, Thermal blooming, Laser beam propagation, 3D modeling, Atmospheric modeling, Thermal modeling, Turbulence, Scintillation, Earth's atmosphere, Refractive index

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Proceedings Article | 1 May 1990 Paper

Effect of a random wind field on thermal blooming instabilities

James Morris, James Viecelli, Thomas Karr

Proceedings Volume 1221, (1990) https://doi.org/10.1117/12.18345

KEYWORDS: Thermal blooming, Atmospheric propagation, Turbulence, Wave propagation, Phase compensation, Laser beam propagation, Refractive index, Absorption, Earth's atmosphere, Neptunium

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We have numerically investigated the effect of random fluctuations on uncompensated (open-loop) and phase-compensated (closed-loop) small -scale thermal blooming instabilities of a collimated beam propagating through refractive index turbulence. We used the ORACLE time-dependent, three space-dimensional, wave-optics code on a Cray X-MP. The Monte Carlo random wind fields, v(z), were exponentially correlated along the propagation direction, z. The small scale instabilities are present up to a threshold value of the rms random wind, beyond which beam propagation appears to be stable; the threshold value is nearly independent of the correlation length as long as the latter is much shorter than both the length of the thermal blooming region and the Rayleigh range of dominant perturbations. We describe our results with a dimensionless shear parameter, S, that is directly proportional to the ratio of the turbulence scintillation rate to the thermal blooming rate. S is defined as: (formula available on paper) is the one-axis variance of the random wind and N is the time derivative of the thermal blooming optical path difference (OPD) in waves/sec. The open-loop calculations use a plane wave “beam” and a uniform medium. The Strehl ration at 50 waves of thermal blooming OPD remains approximately constant while S ≥ 2.3 and then it decreases rapidly as S decreases. The closed-loop calculations use a large Fresnel number finite beam, a non-uniform medium of length sL, absorption - exp(-z/L), and a Hufnagel-Valley typ On2 profile whose r0 Fresnel number was 24. For 10 is less than or equal to Np is less than or equal to 40 we see no evidence of the closed-loop instability at a wind clearing time (20 waves) for S ≥ (54 ± 2)/Np, where (formula available on paper) is twice the actuator spacing simulated by a Fourier filter. This rresult suggests that the ration of the turbulence scintillation rate to the closed-loop gain for a uniform wind determines the threshold.

Proceedings Article | 1 May 1990 Paper

Measurement of the stimulated thermal Rayleigh scattering instability

Thomas Karr, Michael Rushford, John Murray, James Morris

Proceedings Volume 1221, (1990) https://doi.org/10.1117/12.18351

KEYWORDS: Atmospheric propagation, Thermal blooming, Laser beam propagation, Scattering, Rayleigh scattering, Diffusion, Laser scattering, Wave propagation, Earth's atmosphere, Beam propagation method

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Proceedings Article | 1 May 1990 Paper

Linear theory of thermal blooming in turbulence

David Chambers, Thomas Karr, James Morris, P. Cramer, James Viecelli, A. Gautesen

Proceedings Volume 1221, (1990) https://doi.org/10.1117/12.18329

KEYWORDS: Atmospheric propagation, Turbulence, Laser beam propagation, Thermal blooming, Wave propagation, Phase compensation, Earth's atmosphere, Refractive index, Wind energy, Absorption

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Showing 5 of 13 publications

SPIE Conference Volume | 15 December 2016

Unconventional Imaging and Wavefront Sensing XII

SPIE Conference Volume | 8 October 2015

Unconventional Imaging and Wavefront Sensing 2015

SPIE Conference Volume | 30 September 2014

Unconventional Imaging and Wavefront Sensing 2014

SPIE Conference Volume | 2 October 2013

Unconventional Imaging and Wavefront Sensing 2013

SPIE Conference Volume | 19 October 2012

Unconventional Imaging and Wavefront Sensing 2012

Showing 5 of 9 publications

Conference Committee Involvement (21)

Laser Radar Technology and Applications XXX

13 April 2025 | Orlando, Florida, United States

Laser Radar Technology and Applications XXIX

24 April 2024 | National Harbor, Maryland, United States

Laser Radar Technology and Applications XXVIII

3 May 2023 | Orlando, Florida, United States

Laser Radar Technology and Applications XXVII

5 April 2022 | Orlando, Florida, United States

Laser Radar Technology and Applications XXVI

12 April 2021 | Online Only, Florida, United States

Laser Radar Technology and Applications XXV

27 April 2020 | Online Only, California, United States

Laser Radar Technology and Applications XXIV

16 April 2019 | Baltimore, MD, United States

Laser Radar Technology and Applications XXIII

17 April 2018 | Orlando, FL, United States

Unconventional and Indirect Imaging, Image Reconstruction, and Wavefront Sensing 2017

9 August 2017 | San Diego, California, United States

Laser Radar Technology and Applications XXII

11 April 2017 | Anaheim, CA, United States

Unconventional Imaging and Wavefront Sensing XII

31 August 2016 | San Diego, California, United States

Laser Radar Technology and Applications XXI

19 April 2016 | Baltimore, MD, United States

Unconventional Imaging and Wavefront Sensing XI

13 August 2015 | San Diego, California, United States

Unconventional Imaging and Wavefront Sensing X

21 August 2014 | San Diego, California, United States

Unconventional Imaging and Wavefront Sensing IX

26 August 2013 | San Diego, California, United States

Unconventional Imaging and Wavefront Sensing VIII

13 August 2012 | San Diego, California, United States

Unconventional Imaging and Wavefront Sensing VII

21 August 2011 | San Diego, California, United States

Unconventional Imaging VI

1 August 2010 | San Diego, California, United States

Unconventional Imaging V

3 August 2009 | San Diego, California, United States

Unconventional Imaging IV

11 August 2008 | San Diego, California, United States

Enabling Technologies for Law Enforcement and Security

18 November 1996 | Boston, United States

Showing 5 of 21 Conference Committees

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