Dr. Leonard M. Hanssen Profile

Dr. Leonard M. Hanssen

Retired at National Institute of Standards and Technology

SPIE Involvement:

Author | Editor

Publications (53)

SPIE Journal Paper | 23 September 2021

Direct method of extracting broadband complex refractive index from spectrophotometric measurements: an application to polydimethylsiloxane for passive radiative cooling

Braden Czapla, Leonard Hanssen

JPE, Vol. 11, Issue 03, 032105, (September 2021) https://doi.org/10.1117/12.10.1117/1.JPE.11.032105

KEYWORDS: Refractive index, Direct methods, Reflectivity, Spectrophotometry, Transmittance, Optical properties, Reflection, FT-IR spectroscopy, Analytical research, Radiative energy transfer

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Proceedings Article | 20 August 2020 Presentation

Chair Introduction

Leonard Hanssen

Proceedings Volume 11485, 1148502 (2020) https://doi.org/10.1117/12.2581844

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Proceedings Article | 20 August 2020 Presentation + Paper

High temperature reflectometer for spatially resolved spectral directional emissivity of laser powder bed fusion processes

David Deisenroth, Leonard Hanssen, Sergey Mekhontsev

Proceedings Volume 11485, 114850K (2020) https://doi.org/10.1117/12.2568179

KEYWORDS: Reflectometry, Reflectivity, Imaging systems, Light emitting diodes, Point spread functions, Deconvolution, Staring arrays, Stray light, Signal attenuation

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Proceedings Article | 20 August 2020 Presentation + Paper

Direct method of extracting complex refractive index from routine Fourier transform infrared reflectance/transmittance measurements

Braden Czapla, Leonard Hanssen

Proceedings Volume 11485, 114850D (2020) https://doi.org/10.1117/12.2568502

KEYWORDS: Refractive index, Reflectivity, Transmittance, Direct methods, FT-IR spectroscopy, Reflection, Spectrophotometry, Optical properties

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Proceedings Article | 6 September 2017 Presentation + Paper

Low-NEP pyroelectric detectors for calibration of UV and IR sources and detectors

G. Eppeldauer, V. Podobedov, L. Hanssen, C. Cooksey

Proceedings Volume 10378, 1037809 (2017) https://doi.org/10.1117/12.2272582

KEYWORDS: Sensors, Calibration, Light emitting diodes, Pyroelectric detectors, Ultraviolet radiation, Infrared sensors, Spectral calibration, Solid state lighting

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Proceedings Article | 11 October 2016 Paper

Goniometric and hemispherical reflectance and transmittance measurements of fused silica diffusers

Paul Lemaillet, Heather Patrick, Thomas Germer, Leonard Hanssen, B. Carol Johnson, Georgi Georgiev

Proceedings Volume 9961, 996109 (2016) https://doi.org/10.1117/12.2237975

KEYWORDS: IRIS Consortium, Diffusers, Reflectivity, Transmittance, Silica, Scattering, Bidirectional reflectance transmission function, Optical spheres, Sensors, Integrating spheres

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Proceedings Article | 7 September 2016 Paper

Broadband radiometric LED measurements

G. Eppeldauer, C. Cooksey, H. Yoon, L. Hanssen, V. Podobedov, R. Vest, U. Arp, C. Miller

Proceedings Volume 9954, 99540J (2016) https://doi.org/10.1117/12.2237033

KEYWORDS: Ultraviolet radiation, Light emitting diodes, Calibration, Radiometry, Sensors, Pyroelectric detectors, Blue light emitting diodes, Silicon, Standards development, Optical filters

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Proceedings Article | 20 May 2016 Paper

Calibration of spectral responsivity of IR detectors in the range from 0.6 µm to 24 µm

Vyacheslav Podobedov, George Eppeldauer, Leonard Hanssen, Thomas Larason

Proceedings Volume 9819, 98190P (2016) https://doi.org/10.1117/12.2228384

KEYWORDS: Calibration, Infrared detectors, Reflectivity, Spectral calibration, Sensors, Pyroelectric detectors, Radiometry, Monochromators, Optical spheres, Mirrors

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Proceedings Article | 9 May 2016 Paper

Optical design and initial results from NIST's AMMT/TEMPS facility

Steven Grantham, Brandon Lane, Jorge Neira, Sergey Mekhontsev, Mihaela Vlasea, Leonard Hanssen

Proceedings Volume 9738, 97380S (2016) https://doi.org/10.1117/12.2214246

KEYWORDS: Additive manufacturing, Laser processing, Process control, Optical design, Radiometry, Temperature metrology, Feedback control, Mirrors, Beam splitters, Fiber lasers, Imaging systems, Reflectivity, Sensors, Image processing, Optical scanning

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Proceedings Article | 5 June 2013 Paper

Evaluation of dome-input geometry for pyroelectric detectors

J. Zeng, L. Hanssen, G. Eppeldauer

Proceedings Volume 8706, 87060B (2013) https://doi.org/10.1117/12.2016261

KEYWORDS: Radiometry, Domes, Sensors, Reflectivity, Calibration, Pyroelectric detectors, Near infrared, Optical coatings, Infrared radiation, Mirrors

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Proceedings Article | 18 May 2012 Paper

Spectral responsivity calibrations of two types of pyroelectric radiometers using three different methods

J. Zeng, G. Eppeldauer, L. Hanssen, V. Podobedov

Proceedings Volume 8355, 835503 (2012) https://doi.org/10.1117/12.919538

KEYWORDS: Radiometry, Calibration, Sensors, Reflectivity, Spectral calibration, Coating, Domes, Optical filters, Spectroscopy, Spectral resolution

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Proceedings Article | 19 May 2011 Paper

Increased responsivity pyroelectric radiometer with dome input and temperature control

George Eppeldauer, Jinan Zeng, Leonard Hanssen

Proceedings Volume 8014, 801419 (2011) https://doi.org/10.1117/12.883430

KEYWORDS: Radiometry, Sensors, Standards development, Calibration, Infrared radiation, Domes, Resistors, Capacitance, Prototyping, Spectral calibration

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Proceedings Article | 2 September 2010 Paper

Preliminary characterization study of a gold-coated concentrator for hemispherical longwave irradiance measurements

Jinan Zeng, Leonard Hanssen, Ibrahim Reda, Jonathan Scheuch

Proceedings Volume 7792, 77920Z (2010) https://doi.org/10.1117/12.862461

KEYWORDS: Solar concentrators, Transmittance, Gold, Sensors, Integrating spheres, Diffusers, Temperature metrology, Bidirectional reflectance transmission function, Signal detection, Compound parabolic concentrators

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Proceedings Article | 1 October 2009 Paper

Stochastic modeling of non-Lambertian surfaces for Monte Carlo computations in optical radiometry

Leonard Hanssen, Alexander Prokhorov

Proceedings Volume 7427, 742707 (2009) https://doi.org/10.1117/12.826468

KEYWORDS: Bidirectional reflectance transmission function, Reflection, Monte Carlo methods, Radio optics, Radiometry, 3D modeling, Stochastic processes, Ray tracing, Instrument modeling, Spherical lenses

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Proceedings Article | 2 September 2009 Paper

Development of an infrared optical scattering instrument from 1 μm to 5 μm

Jinan Zeng, Leonard Hanssen

Proceedings Volume 7453, 74530Q (2009) https://doi.org/10.1117/12.829580

KEYWORDS: Bidirectional reflectance transmission function, Tunable lasers, Optical parametric oscillators, Sensors, Speckle, Infrared radiation, Scattering, Reflectivity, Polarization, Semiconductor lasers

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Proceedings Article | 2 September 2009 Paper

Spectral irradiance responsivity calibration of InSb radiometers using the improved IR-SIRCUS at NIST

Jinan Zeng, Howard Yoon, George Eppeldauer, Leonard Hanssen, Joseph Rice

Proceedings Volume 7453, 74530N (2009) https://doi.org/10.1117/12.828699

KEYWORDS: Radiometry, Calibration, Integrating spheres, Sensors, Spectral calibration, Speckle, Optical parametric oscillators, Optical filters, Optical spheres, Tunable lasers

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Proceedings Article | 29 August 2009 Paper

Pupil alignment reference (PAR) for the Mid-Infrared Instrument (MIRI) for optical alignment and verification on the Integrated Science Instrument Module (ISIM) in James Webb Space Telescope (JWST)

Cagatay Aymergen, Phillip Driggers, Raymond Ohl, Ray Lundquist, Pam Davila, Brent Bos, Scott Antonille, David Kubalak, Suong Le, Leonard Hanssen, Vilem Mikula, Claef Hakun, Corina Guishard, Jeffrey Guzek, Joe Connelly, Joseph McMann

Proceedings Volume 7433, 74330P (2009) https://doi.org/10.1117/12.826286

KEYWORDS: James Webb Space Telescope, Optical alignment, Interfaces, Cryogenics, Bidirectional reflectance transmission function, Inspection, Space telescopes, Reflectivity, Mirrors, Telescopes

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Proceedings Article | 3 September 2008 Paper

Angle-dependent infrared reflectance measurements in support of VIIRS

Simon Kaplan, Enrique Iglesias, Leonard Hanssen

Proceedings Volume 7082, 70820X (2008) https://doi.org/10.1117/12.798263

KEYWORDS: Reflectivity, Sensors, Mirrors, FT-IR spectroscopy, Gold, Silver, Absorption, Reflectometry, Infrared radiation, Spectroscopy

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Proceedings Article | 3 September 2008 Paper

Calibration of the spectral radiant power responsivity of windowed pyroelectric radiometers from 785 nm to 14 μm

Jinan Zeng, Leonard Hanssen

Proceedings Volume 7082, 70820Y (2008) https://doi.org/10.1117/12.799665

KEYWORDS: Sensors, Reflectivity, Calibration, Radiometry, Tunable lasers, Carbon dioxide lasers, Optical parametric oscillators, Spectral calibration, Infrared sensors, Infrared detectors

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Proceedings Article | 29 August 2008 Paper

An infrared laser-based reflectometer for low reflectance measurements of samples and cavity structures

Jinan Zeng, Leonard Hanssen

Proceedings Volume 7065, 70650F (2008) https://doi.org/10.1117/12.796186

KEYWORDS: Reflectivity, Optical spheres, Integrating spheres, Black bodies, Sensors, Polarization, Tunable lasers, Germanium, Bidirectional reflectance transmission function, Infrared lasers

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Proceedings Article | 29 August 2008 Paper

A procedural model of reflection from random rough surfaces

Leonard Hanssen, Alexander Prokhorov

Proceedings Volume 7065, 70650W (2008) https://doi.org/10.1117/12.796142

KEYWORDS: Bidirectional reflectance transmission function, Reflection, Monte Carlo methods, 3D modeling, Reflectivity, Data modeling, Geometrical optics, Mathematical modeling, Radio optics, Spherical lenses

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Proceedings Article | 29 August 2008 Paper

A comparison of optical properties between high density and low density sintered PTFE

Benjamin Tsai, David Allen, Leonard Hanssen, Boris Wilthan, Jinan Zeng

Proceedings Volume 7065, 70650Y (2008) https://doi.org/10.1117/12.798138

KEYWORDS: Bidirectional reflectance transmission function, Transmittance, FT-IR spectroscopy, Reflectivity, Optical properties, Ultraviolet radiation, Sensors, Infrared radiation, Diffusers, Particles

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Proceedings Article | 21 September 2007 Paper

Tunable filter comparator for spectral calibration of near-ambient temperature blackbodies

V. Khromchenko, S. Mekhontsev, L. Hanssen

Proceedings Volume 6678, 66781E (2007) https://doi.org/10.1117/12.735890

KEYWORDS: Black bodies, Temperature metrology, Thermography, Calibration, Infrared imaging, Infrared radiation, Radiometry, Mirrors, Sensors, Tunable filters

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Proceedings Article | 10 May 2006 Paper

Development and calibration of pyroelectric radiometer standards at NIST

G. Eppeldauer, J. Zeng, L. Hanssen

Proceedings Volume 6201, 620119 (2006) https://doi.org/10.1117/12.665997

KEYWORDS: Radiometry, Sensors, Calibration, Reflectivity, Standards development, Pyroelectric detectors, Infrared radiation, Domes, Temperature metrology, Signal detection

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Proceedings Article | 18 April 2006 Paper

Water heat pipe blackbody as a reference spectral radiance source between 50°C and 250°C

M. Noorma, S. Mekhontsev, V. Khromchenko, M. Litorja, C. Cagran, J. Zeng, L. Hanssen

Proceedings Volume 6205, 620502 (2006) https://doi.org/10.1117/12.667257

KEYWORDS: Black bodies, Temperature metrology, Calibration, Reflectivity, Infrared radiation, Standards development, Gas lasers, Pyrometry, Aluminum, Thermography

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Proceedings Article | 18 April 2006 Paper

Radiation properties of IR calibrators with V-grooved surfaces

Alexander Prokhorov, Leonard Hanssen, Sergey Mekhontsev

Proceedings Volume 6205, 620505 (2006) https://doi.org/10.1117/12.667557

KEYWORDS: Reflection, Reflectivity, Data modeling, Calibration, Black bodies, Infrared radiation, Sensors, Radiometry, Numerical modeling, Monte Carlo methods

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Proceedings Article | 18 April 2006 Paper

Design and characterization of Si and InGaAs pyrometers for radiance temperature scale realization between 232 °C and 962 °C

M. Noorma, S. Mekhontsev, V. Khromchenko, A. Gura, M. Litorja, B. Tsai, L. Hanssen

Proceedings Volume 6205, 620501 (2006) https://doi.org/10.1117/12.667253

KEYWORDS: Temperature metrology, Calibration, Pyrometry, Silver, Zinc, Tin, Black bodies, Radiometry, Silicon, Indium gallium arsenide

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Proceedings Article | 18 April 2006 Paper

IR spectral characterization of customer blackbody sources: first calibration results

S. Mekhontsev, M. Noorma, A. Prokhorov, L. Hanssen

Proceedings Volume 6205, 620503 (2006) https://doi.org/10.1117/12.667523

KEYWORDS: Black bodies, Temperature metrology, Pyrometry, Cesium, Calibration, FT-IR spectroscopy, Infrared radiation, Sodium, Spectrometers, Zinc

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Proceedings Article | 12 April 2004 Paper

Infrared spectral emissivity characterization facility at NIST

Leonard Hanssen, Sergey Mekhontsev, Vladimir Khromchenko

Proceedings Volume 5405, (2004) https://doi.org/10.1117/12.542224

KEYWORDS: Black bodies, Temperature metrology, Mirrors, Reflectometry, Optical spheres, Radiometry, Fourier transforms, Integrating spheres, Infrared radiation, Spectrometers

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Proceedings Article | 14 November 2003 Paper

Specular baffle for improved infrared integrating sphere performance

Leonard Hanssen, Alexander Prokhorov, Vladimir Khromchenko

Proceedings Volume 5192, (2003) https://doi.org/10.1117/12.508299

KEYWORDS: Optical spheres, Sensors, Integrating spheres, Reflectivity, Infrared radiation, Gold, Ray tracing, Optical coatings, Spherical lenses, Reflectometry

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Proceedings Article | 14 November 2003 Paper

Analytical evaluation and correction of port loss error in integrating sphere reflectometers

Alexander Prokhorov, Sergey Mekhontsev, Leonard Hanssen

Proceedings Volume 5192, (2003) https://doi.org/10.1117/12.508326

KEYWORDS: Reflectivity, Optical spheres, Bidirectional reflectance transmission function, Error analysis, Integrating spheres, Solids, Reflectometry, High dynamic range imaging, Sensors, Statistical modeling

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Proceedings Article | 14 November 2003 Paper

Algorithmic model of microfacet BRDF for Monte Carlo calculation of optical radiation transfer

Alexander Prokhorov, Leonard Hanssen

Proceedings Volume 5192, (2003) https://doi.org/10.1117/12.508577

KEYWORDS: Bidirectional reflectance transmission function, Reflectivity, Reflection, Ray tracing, Monte Carlo methods, Data modeling, Geometrical optics, Specular reflections, Mathematical modeling, Radio optics

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Proceedings Article | 8 August 2003 Paper

Linearity characterization of NIST's infrared spectral regular transmittance and reflectance scales

Leonard Hanssen, Simon Kaplan

Proceedings Volume 4826, (2003) https://doi.org/10.1117/12.514482

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Proceedings Article | 18 December 2002 Paper

Spectral responsivity determination of a transfer-standard pyroelectric radiometer

George Eppeldauer, Miklos Racz, Leonard Hanssen

Proceedings Volume 4818, (2002) https://doi.org/10.1117/12.450561

KEYWORDS: Reflectivity, Sensors, Radiometry, Pyroelectric detectors, Calibration, Coating, Ultraviolet radiation, Spectrophotometry, Infrared radiation, Fourier transforms

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Proceedings Article | 16 August 2002 Paper

Numerical modeling of an integrating sphere radiation source

Alexander Prokhorov, Leonard Hanssen

Proceedings Volume 4775, (2002) https://doi.org/10.1117/12.479642

KEYWORDS: Optical spheres, Intelligence systems, Ray tracing, Integrating spheres, Reflection, Calibration, Reflectivity, Monte Carlo methods, Algorithm development, Spherical lenses

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Proceedings Article | 11 October 2000 Paper

Intercomparison of regular spectral transmittance and reflectance measurements with FTIR- and monochromator-based spectrophotometers

Simon Kaplan, Leonard Hanssen, Edward Early, Maria Nadal

Proceedings Volume 4103, (2000) https://doi.org/10.1117/12.403570

KEYWORDS: Transmittance, Reflectivity, FT-IR spectroscopy, Monochromators, Sensors, Mirrors, Optical spheres, Spectrophotometry, Solids, Optical filters

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Proceedings Article | 11 October 2000 Paper

Comparison and development of absorption peak determination algorithms for wavelength standards

Changjiang Zhu, Leonard Hanssen

Proceedings Volume 4103, (2000) https://doi.org/10.1117/12.403571

KEYWORDS: Apodization, Standards development, Algorithm development, Absorption, Calibration, Fourier transforms, Sensors, Optimization (mathematics), Spectrometers, Infrared radiation

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Proceedings Article | 11 October 2000 Paper

Development of an adiabatic laser calorimeter

Etsuo Kawate, Leonard Hanssen, Simon Kaplan, Raju Datla

Proceedings Volume 4103, (2000) https://doi.org/10.1117/12.403579

KEYWORDS: Absorption, Temperature metrology, Sensors, Laser development, Copper, Laser applications, Infrared radiation, Potassium, Resistors, Carbon dioxide lasers

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Proceedings Article | 11 October 2000 Paper

Angle-dependent absolute infrared reflectance and transmittance measurements

Simon Kaplan, Leonard Hanssen

Proceedings Volume 4103, (2000) https://doi.org/10.1117/12.403573

KEYWORDS: Reflectivity, Transmittance, Sensors, Polarizers, Mirrors, Silicon, Infrared radiation, Germanium, Optical spheres, Refraction

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Proceedings Article | 25 October 1999 Paper

FT-IR-based ellipsometer using high-quality Brewster-angle polarizers

Simon Kaplan, Leonard Hanssen

Proceedings Volume 3754, (1999) https://doi.org/10.1117/12.366338

KEYWORDS: Sensors, Polarizers, Signal detection, Silicon, Infrared spectroscopy, FT-IR spectroscopy, Ellipsometry, Polarization, Spectroscopy, Infrared radiation

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