Prof. James R. Leger Profile

Prof. James R. Leger

Professor at Univ of Minnesota Twin Cities

SPIE Involvement:

Conference Program Committee | Author | Instructor

Publications (40)

Proceedings Article | 3 October 2023 Presentation + Paper

Maximizing the non-line-of-sight information content retrievable from passive scattered light fields: a comparison between visible, long wave infrared, and terahertz radiation

Takahiro Sasaki, James Leger

Proceedings Volume 12693, 126930U (2023) https://doi.org/10.1117/12.2677727

KEYWORDS: Non-line-of-sight propagation, Terahertz radiation, Long wavelength infrared, Wigner distribution functions, Diffraction, Convolution, Light scattering, Scattered light, Optical design, Imaging systems

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Proceedings Article | 20 August 2020 Presentation + Paper

A novel design for beamforming the Breakthrough Starshot laser array

James Leger

Proceedings Volume 11486, 114860D (2020) https://doi.org/10.1117/12.2569134

KEYWORDS: Coherent beam combination, Coherent optics, Wavefronts, Phased array optics, Space operations, Phase shifts, Neodymium, Stars, Laser optics, Atmospheric turbulence, Phased arrays

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Proceedings Article | 4 March 2019 Presentation + Paper

Kramers-Kronig self-phasing effect in passive beam combining resonators

W. Minster Kunkel, James Leger

Proceedings Volume 10904, 109041N (2019) https://doi.org/10.1117/12.2506693

KEYWORDS: Resonators, Wavelength tuning, Destructive interference, Kerr effect, Fabry–Perot interferometers, Reflectivity, Constructive interference, Fiber coupled lasers, Laser resonators, Spatial filters

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Proceedings Article | 18 September 2018 Presentation + Paper

Light-field reconstruction from scattered light using plenoptic data

Takahiro Sasaki, James Leger

Proceedings Volume 10772, 1077203 (2018) https://doi.org/10.1117/12.2321668

KEYWORDS: Scattering, Light scattering, Bidirectional reflectance transmission function, Cameras, Computer graphics, Reconstruction algorithms, Non-line-of-sight propagation, Inverse problems, Light sources and illumination, Photography

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Proceedings Article | 16 February 2018 Presentation + Paper

Gradient-index beam shapers: fabricated devices and 3D design method

W. Minster Kunkel, Ali Ghoreyshi, Glen Douglass, Simon Gross, Michael Withford, James Leger

Proceedings Volume 10518, 105181S (2018) https://doi.org/10.1117/12.2290909

KEYWORDS: GRIN lenses, Refractive index, Waveguides, Beam shaping, Wavefronts, Femtosecond phenomena, Gaussian beams, Diffraction, Phase retrieval, Wave propagation

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Proceedings Article | 22 February 2017 Presentation + Paper

Investigation of self-phasing dynamics in a Q-switched passively coupled two-gain-element fiber laser array

Hung-Sheng Chiang, James Leger

Proceedings Volume 10083, 100831Y (2017) https://doi.org/10.1117/12.2252993

KEYWORDS: Fiber lasers, Q switched lasers, Q switching, Acousto-optics, Free space optics, Laser resonators, Diffraction gratings, Modes of laser operation, Fringe analysis, Kerr effect, Mode locking, Signal detection, Phase measurement, Continuous wave operation

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Proceedings Article | 20 February 2017 Presentation + Paper

Numerical design of gradient-index beam shapers

W. Minster Kunkel, James Leger

Proceedings Volume 10090, 100900Y (2017) https://doi.org/10.1117/12.2253122

KEYWORDS: GRIN lenses, Beam shaping, Gradient-index optics, Optical design, Additive manufacturing, Phase retrieval, Lenses, Fiber optic communications, 3D modeling, 3D printing, Refractive index, Wavefronts, Chemical elements, Wave propagation, Diffraction, Beam propagation method

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Proceedings Article | 1 September 2015 Paper

An iterative approach to measuring two-dimensional gradient-index profiles based on external measurements of laser beam deflection

Di Lin, James Leger

Proceedings Volume 9576, 95760G (2015) https://doi.org/10.1117/12.2186808

KEYWORDS: Refractive index, Dynamical systems, Laser beam diagnostics, GRIN lenses, Optical testing, Ray tracing, Particles, Reconstruction algorithms, Inverse problems, Chemical elements

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Proceedings Article | 21 June 2015 Paper

Nondestructive measurement of two-dimensional refractive index profiles by deflectometry

Di Lin, James Leger

Proceedings Volume 9526, 95260Q (2015) https://doi.org/10.1117/12.2184856

KEYWORDS: Laser beam diagnostics, Deflectometry, Ray tracing, Refractive index, GRIN lenses, Quantization, Error analysis, Gradient-index optics, Nondestructive evaluation, Inverse problems

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Proceedings Article | 3 March 2015 Paper

Uncovering the physical origin of self-phasing in coupled fiber lasers

Hung-Sheng Chiang, James Leger

Proceedings Volume 9343, 93431A (2015) https://doi.org/10.1117/12.2085406

KEYWORDS: Fiber amplifiers, Phase shifts, Laser resonators, Diffraction gratings, Binary data, Fiber lasers, Semiconductor lasers, Beam splitters, Laser damage threshold, Mirrors

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Proceedings Article | 12 March 2014 Paper

The effect of polarization in passive coherent beam combining of fiber lasers

Hung-Sheng Chiang, James Leger, Emese Huszar, Johan Nilsson, Jayanta Sahu

Proceedings Volume 8961, 89612B (2014) https://doi.org/10.1117/12.2041012

KEYWORDS: Polarization, Polarizers, Phase shifts, Fiber lasers, Diffraction gratings, Laser beam diagnostics, Laser resonators, Phase measurement, Semiconductor lasers, Polarization maintaining fibers

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Proceedings Article | 7 March 2014 Paper

Nonlinear effects in coherently coupled laser resonators

James Leger, Hung-Sheng Chiang

Proceedings Volume 8960, 89601E (2014) https://doi.org/10.1117/12.2042910

KEYWORDS: Phase shifts, Phase measurement, Fiber lasers, Diffraction gratings, Laser resonators, Laser beam diagnostics, Phase shifting, Mirrors, Beam shaping, Refraction

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Proceedings Article | 9 September 2013 Paper

Experimental verification of spectral grating interference in multiplexed volume holograms employed as broadband dispersive elements for solar concentrators

G. Ingersoll, D. Lin, J. Leger

Proceedings Volume 8821, 882107 (2013) https://doi.org/10.1117/12.2024295

KEYWORDS: Diffraction gratings, Multiplexing, Diffraction, Fiber Bragg gratings, Solar cells, Systems modeling, Solar energy, Data modeling, Holograms, Holography

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SPIE Journal Paper | 16 July 2013

One-dimensional gradient-index metrology based on ray slope measurements using a bootstrap algorithm

Di Lin, James Leger, Mint Kunkel, Peter McCarthy

OE, Vol. 52, Issue 11, 112108, (July 2013) https://doi.org/10.1117/12.10.1117/1.OE.52.11.112108

KEYWORDS: Error analysis, GRIN lenses, Ray tracing, Refractive index, Metrology, Laser beam diagnostics, Computer simulations, Geometrical optics, Gradient-index optics, Optical engineering

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Proceedings Article | 12 March 2013 Paper

Recent advances in coupled laser cavity design

James Leger, Hung-Sheng Chiang, Johan Nilsson, Junhau Ji, Jayanta Sahu

Proceedings Volume 8600, 86000S (2013) https://doi.org/10.1117/12.2005628

KEYWORDS: Fiber lasers, Q switching, Laser resonators, Laser systems engineering, Laser development, Superposition, Q switched lasers, Q switches, Optical components, Lasers

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Proceedings Article | 15 October 2012 Paper

Graded-index design in coherent beam shaping

Di Lin, James Leger

Proceedings Volume 8490, 849005 (2012) https://doi.org/10.1117/12.928714

KEYWORDS: GRIN lenses, Wavefronts, Refractive index, Geometrical optics, Ray tracing, Inverse optics, Beam shaping, Gaussian beams, Integration, Structural design

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Proceedings Article | 1 February 2012 Paper

A comparison of passive coherent beam combining architectures: experimental results

Chenhao Wan, Bradley Tiffany, James Leger

Proceedings Volume 8236, 823603 (2012) https://doi.org/10.1117/12.906932

KEYWORDS: Spatial filters, Superposition, Polarization, Lasers, Mirrors, Beam splitters, Laser systems engineering, Nd:YAG lasers, Reflectivity, Wave plates

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Proceedings Article | 18 February 2010 Paper

Common cavity resonators for passive laser beam combining: effects of path length errors

J. Leger, M. Khajavikhan, C. Wan

Proceedings Volume 7579, 75790J (2010) https://doi.org/10.1117/12.843289

KEYWORDS: Mirrors, Polarization, Reflectivity, Beam splitters, Laser resonators, Spatial filters, Electronic filtering, Resonators, Cavity resonators, Tolerancing

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Proceedings Article | 24 August 2009 Paper

Beam shaping in laser resonators and coherent laser arrays: an overview and current state of the art

J. Leger, M. Khajavikhan, B. Tiffany

Proceedings Volume 7430, 74300L (2009) https://doi.org/10.1117/12.828524

KEYWORDS: Mirrors, Laser resonators, Resonators, Beam shaping, Optical filters, Tolerancing, Modes of laser operation, Phase shifts, Fiber lasers, Beam splitters

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Proceedings Article | 20 February 2009 Paper

Theoretical analysis of multiplexed volume holograms for spectral beam combining

G. Ingersoll, J. Leger

Proceedings Volume 7195, 71951P (2009) https://doi.org/10.1117/12.809524

KEYWORDS: Holograms, Diffraction gratings, Volume holography, Diffraction, Optical design, Multiplexing, Holography, Fiber Bragg gratings, Chemical elements, Differential equations

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Proceedings Article | 27 September 2007 Paper

GRIN-optics-based hyperspectral imaging micro-sensor

Wei Zhou, James Leger

Proceedings Volume 6765, 676502 (2007) https://doi.org/10.1117/12.754011

KEYWORDS: Channel projecting optics, GRIN lenses, Diffraction gratings, Sensors, Spectroscopy, Hyperspectral imaging, Optical design, Diffraction, Etching, Image sensors

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Proceedings Article | 13 September 2007 Paper

Spatially inhomogeneous polarization in laser beam shaping

Bing Hao, James Leger

Proceedings Volume 6682, 66820Y (2007) https://doi.org/10.1117/12.734207

KEYWORDS: Polarization, Beam shaping, Diffraction, Modulation, Algorithms, Gaussian beams, Optical components, Phase modulation, Near field optics, Laser applications

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Proceedings Article | 25 August 2006 Paper

Smallest 1D flat-top focus by polarization manipulation

Bing Hao, James Leger

Proceedings Volume 6290, 629001 (2006) https://doi.org/10.1117/12.679267

KEYWORDS: Polarization, Beam shaping, Computer generated holography, Algorithms, Optimization (mathematics), Quantization, Optical components, Diffraction, Optical recording, Optical tweezers

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SPIE Journal Paper | 1 April 2006

Fabrication of large-sag aspheric micro-optics with nanometer accuracy using electron-beam lithography on curved substrates

Zhaohui Yang, James Leger

OE, Vol. 45, Issue 04, 043401, (April 2006) https://doi.org/10.1117/12.10.1117/1.2190627

KEYWORDS: Mirrors, Aspheric optics, Vertical cavity surface emitting lasers, Lithography, Laser resonators, Aspheric lenses, Optical fabrication, Phase conjugation, Micro optics, Spherical lenses

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Proceedings Article | 15 February 2006 Paper

Spectral properties of three-mirror laser resonators

Zhaohui Yang, James Leger

Proceedings Volume 6101, 610104 (2006) https://doi.org/10.1117/12.660681

KEYWORDS: Fabry–Perot interferometers, Resonators, Mirrors, Reflectivity, Phase conjugation, Laser resonators, Diffraction, Aspheric lenses, Semiconductor lasers, Aspheric optics

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Proceedings Article | 1 June 2004 Paper

The applications of aspheric feedback mirror in extended-cavity laser resonators

Zhaohui Yang, James Leger

Proceedings Volume 5333, (2004) https://doi.org/10.1117/12.549480

KEYWORDS: Mirrors, Resonators, Aspheric lenses, Aspheric optics, Phase conjugation, Fabry–Perot interferometers, Laser resonators, Diffraction, Vertical cavity surface emitting lasers, Wavefronts

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Proceedings Article | 10 November 2003 Paper

Imaging microspectrometer with space-variant adaptive dispersion incorporating a MEMS mirror array

Eric Shields, Wei Liu, Joseph Talghader, James Leger

Proceedings Volume 5177, (2003) https://doi.org/10.1117/12.505681

KEYWORDS: Mirrors, Spectroscopy, Microelectromechanical systems, Sensors, Photoresist materials, Optical components, Imaging systems, Diffraction gratings, Photomasks, Optical design

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Proceedings Article | 11 November 2002 Paper

Design and Implementation of a rotationally symmetric ellipsometer

Qiwen Zhan, James Leger

Proceedings Volume 4779, (2002) https://doi.org/10.1117/12.451710

KEYWORDS: Signal detection, Polarization, Spatial resolution, Objectives, Thin films, Wave plates, Sensors, Signal to noise ratio, Beam splitters, Helium neon lasers

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Proceedings Article | 28 May 2002 Open Access

University/industry cooperative teaching laboratory for undergraduate education

James Leger

Proceedings Volume 4588, (2002) https://doi.org/10.1117/12.468722

KEYWORDS: Diffraction, Fourier transforms, Modulation transfer functions, Charge-coupled devices, Speckle, CCD cameras, Near field diffraction, Diffraction gratings, Visibility, Helium neon lasers

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Proceedings Article | 26 December 2001 Paper

Imaging ellipsometry for high-spatial-resolution metrology

Qiwen Zhan, James Leger

Proceedings Volume 4435, (2001) https://doi.org/10.1117/12.451132

KEYWORDS: Polarization, Objectives, Metrology, Ellipsometry, Dielectric polarization, Diffraction, Silicon, Thin films, Wave plates, Spatial filters

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Proceedings Article | 1 June 1999 Paper

Micro-optical elements fabricated and replicated in semiconductor materials

Fredrik Nikolajeff, James Leger, Todd Ballen

Proceedings Volume 3633, (1999) https://doi.org/10.1117/12.349337

KEYWORDS: Gallium arsenide, Etching, Polymers, Nickel, Polymer thin films, Micromirrors, Reactive ion etching, Plasma, Semiconductor materials, Prisms

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Proceedings Article | 29 April 1999 Paper

Controlling and utilizing aberrations in solid state lasers

Siamak Makki, James Leger

Proceedings Volume 3729, (1999) https://doi.org/10.1117/12.346790

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Proceedings Article | 13 May 1998 Paper

Micro-optics in VCSEL and solid state laser resonators

James Leger, G. Chen, Barry Koch, Siamak Makki, Anand Gopinath

Proceedings Volume 3267, (1998) https://doi.org/10.1117/12.308098

KEYWORDS: Vertical cavity surface emitting lasers, Fabry–Perot interferometers, Reflectivity, Mirrors, Spatial filters, Laser resonators, Resonators, Solid state lasers, GRIN lenses, Optical components

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Proceedings Article | 31 March 1997 Paper

Simplified intracavity phase plates for increasing modal discrimination in a laser cavity

Anatoly Napartovich, Nickolai Elkin, Vera Troschieva, Dmitri Vysotsky, James Leger

Proceedings Volume 2986, (1997) https://doi.org/10.1117/12.270011

KEYWORDS: Mirrors, Laser resonators, Resonators, Chemical elements, Gaussian beams, Reflectivity, Spherical lenses, Wave propagation, Phase shift keying, Phase modulation

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Proceedings Article | 29 April 1996 Paper

Modal properties of laser arrays using diffractive mode-selecting mirrors

James Leger, Greg Mowry

Proceedings Volume 2792, (1996) https://doi.org/10.1117/12.239177

KEYWORDS: Mirrors, Semiconductor lasers, Laser resonators, Resonators, Reflectivity, Diffraction, Carbon dioxide lasers, Mode locking, Output couplers, Lithium

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Proceedings Article | 18 August 1995 Paper

Advances in diffractive optical laser resonators

James Leger, D. Chen, Greg Mowry

Proceedings Volume 2622, (1995) https://doi.org/10.1117/12.216810

KEYWORDS: Mirrors, Laser resonators, Laser optics, Chemical elements, Laser development, Laser crystals, Resonators, Quantization, Optical components, Diffraction

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Proceedings Article | 12 May 1995 Paper

Applications of diffractive optics to diode laser arrays and amplifiers

James Leger, Greg Mowry

Proceedings Volume 2383, (1995) https://doi.org/10.1117/12.209025

KEYWORDS: Mirrors, Semiconductor lasers, Optical amplifiers, Resonators, Reflectivity, Laser development, Diffraction, Laser resonators, Waveguides, Monte Carlo methods

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Proceedings Article | 26 June 1992 Paper

Effects of path-length errors on external-cavity semiconductor laser arrays

Todd Rider, James Leger

Proceedings Volume 1634, (1992) https://doi.org/10.1117/12.59150

KEYWORDS: Semiconductor lasers, Laser applications, Phase shifts, Mirrors, Microlens, Technologies and applications, Microlens array, Oscillators, Refraction, Laser resonators

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Proceedings Article | 1 September 1990 Paper

Stereoscopic displays for terrain database visualization

Harry Veron, David Southard, James Leger, John Conway

Proceedings Volume 1256, (1990) https://doi.org/10.1117/12.19897

KEYWORDS: Stereoscopic displays, Visualization, Stereo holograms, Data modeling, Eye, Databases, 3D modeling, Liquid crystals, 3D image processing, Camera shutters

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Proceedings Article | 1 May 1990 Paper

Effects of liquid crystals on diffractive coupling in a diode laser external cavity

J. Michael Finlan, Scott Hamilton, James Leger

Proceedings Volume 1219, (1990) https://doi.org/10.1117/12.18275

KEYWORDS: Liquid crystals, Semiconductor lasers, Laser applications, Mirrors, Modulators, Microlens array, Laser optics, Video, Collimation, Coherence (optics)

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Showing 5 of 40 publications

Conference Committee Involvement (24)

Laser Resonators, Microresonators, and Beam Control XXVII

25 January 2025 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XXVI

30 January 2024 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XXV

31 January 2023 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XXIV

24 January 2022 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XXIII

6 March 2021 | Online Only, California, United States

Laser Resonators, Microresonators, and Beam Control XXII

3 February 2020 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XXI

4 February 2019 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XX

29 January 2018 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XIX

30 January 2017 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XVIII

15 February 2016 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XVII

9 February 2015 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XVI

3 February 2014 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XV

3 February 2013 | San Francisco, California, United States

Laser Resonators, Microresonators, and Beam Control XIV

22 January 2012 | San Francisco, California, United States

Laser Resonators and Beam Control XIII

23 January 2011 | San Francisco, California, United States

Laser Resonators and Beam Control XII

24 January 2010 | San Francisco, California, United States

Laser Resonators and Beam Control XI

26 January 2009 | San Jose, California, United States

Laser Resonators and Beam Control X

21 January 2008 | San Jose, California, United States

Laser Resonators and Beam Control IX

22 January 2007 | San Jose, California, United States

Laser Resonators and Beam Control IX

25 January 2006 | San Jose, California, United States

Laser Resonators and Beam Control VIII

25 January 2005 | San Jose, California, United States

Laser Resonators and Beam Control VII

28 January 2004 | San Jose, Ca, United States

Wave-Optical Systems Engineering II

3 August 2003 | San Diego, California, United States

Laser Resonators and Beam Control VI

29 January 2003 | San Jose, CA, United States

Showing 5 of 24 Conference Committees

Course Instructor

SC008: Microlens Arrays: Properties and Applications

Microlens arrays provide a flexible and powerful technique for solving a variety of optical design problems. This course will provide an introduction to the types of microlens arrays currently available and their optical characteristics. Topics include optical properties of arrays, fabrication techniques, and applications to coherent and incoherent imaging systems.

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