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Publications

Search Publications by John H. Lehman

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Displaying 26 - 50 of 143

Carbon Nanotube-Based Black Coatings

February 15, 2018
Author(s)
John H. Lehman, Christopher S. Yung, Nathan A. Tomlin, Davis R. Conklin, Michelle S. Stephens
It has been shown that coatings comprised of carbon nanotubes are very black; that is, characterized by low reflectance over a broad wavelength range from the visible to far infrared. Arguably there is no other material that is comparable. This is

Geometric contributions to chopper wheel optical attenuation uncertainty

December 9, 2017
Author(s)
Matthew T. Spidell, Joshua A. Hadler, Michelle S. Stephens, John H. Lehman, Paul A. Williams
Calibrated reflective optical choppers are used in NIST’s high power laser calibration services due to their advantages in performance and safety over wedges and semi-transparent materials for beam power reduction. While the design, operation, and

On-site multi-kilowatt laser power meter calibration using radiation pressure

December 1, 2017
Author(s)
Paul A. Williams, Joshua A. Hadler, Brian J. Simonds, John H. Lehman
We have demonstrated the calibration of a thermal power meter against a radiation-pressure power meter in the range of 20 kW in a manufacturing test environment. The results were compared to a traditional calorimeter-based laboratory calibration undertaken

Plasma modification of vertically aligned carbon nanotubes: superhydrophobic surfaces with ultra- low reflectance

November 2, 2017
Author(s)
Christopher S. Yung, Nathan A. Tomlin, Karl Heuerman, Mark W. Keller, Malcolm G. White, Michelle S. Stephens, John H. Lehman
Vertically aligned carbon nanotubes (VACNTs) are excellent broadband (UV–VIS–IR) absorbers of light that can be made even darker with plasma treatments. Modification of VACNTs using O2 and/or CF4 plasmas is shown to have a significant impact on the

Verification of Calibration Methods for Determining Photon-Counting Detection Efficiency using Superconducting Nano-Wire Single Photon Detectors

September 4, 2017
Author(s)
Igor Vayshenker, Robert D. Horansky, John H. Lehman, Malcolm G. White, Sae Woo Nam, Ingmar Mueller, Lutz Werner, G. Wuebbeler
In the recent years several ways to radiometrically calibrate optical fiber-coupled detectors have been developed. However, fiber-coupled calibration methods for single photon detectors have not been compared by national metrology institutes validating the

Prototype Tests of a Miniature Radiation Pressure Sensor

July 2, 2017
Author(s)
Alexandra B. Artusio-Glimpse, Paul A. Williams, Nathan A. Tomlin, Ivan Ryger, Michelle S. Stephens, John H. Lehman
Using reflection, radiation pressure (RP) sensors provide a means for in-situ power measurement simply and accurately. The first realization of multi-kW RP power meters (RPPM) established a new paradigm of optical power measurement technology [1]. Our

Silicon Micromachined Capacitive Force Scale: The Way to Improved Radiation Pressure Sensing

July 2, 2017
Author(s)
Ivan Ryger, Paul A. Williams, Nathan A. Tomlin, Alexandra B. Artusio-Glimpse, Michelle S. Stephens, Matthew T. Spidell, John H. Lehman
Measurement of high optical power using radiation pressure sensing [1] is attractive for its non-absorbing power measurment allowing compact sensor dimensions, faster response times and negligible optical power dissipation compared to standard thermal

Noise characteristics of thermistors: measurement methods and results of selected devices

February 13, 2017
Author(s)
Ivan Ryger, Michelle S. Stephens, Malcolm G. White, Nathan A. Tomlin, Matthew T. Spidell, John H. Lehman, Dave Harber
As part of the development of a spectrally-uniform room-temperature absolute radiometer, we have studied the electrical noise of several bulk chip thermistors in order to estimate the noise floor and optical dynamic range. Understanding the fundamental

A Planar Hyperblack Absolute Radiometer

November 14, 2016
Author(s)
John H. Lehman, Michelle S. Stephens, Malcolm G. White, Andreas Steiger, Christian Monte, Joerg Hollandt, Ivan Ryger, Mathias Kehrt, Marla L. Dowell
The absolute responsivity of a planar radiometer fabricated from micromachined silicon and having carbon nanotubes as the absorber and thermistor was measured in the visible and far infrared (free-field terahertz) wavelength range by means of detector

Low noise resistive bolometer read out for wideband room temperature infrared detector

September 25, 2016
Author(s)
Ivan Ryger, Malcolm G. White, Nathan A. Tomlin, John H. Lehman, Peter Lobotka, Dave Harber
The absolute electrical substitution radiometer is the way to ensure highly accurate and stable measurement of optical power in wide range of optical wavelength. Its sensitivity is mainly determined by temperature stability of the equithermal bath and

Low noise thermistor read out for wideband room temperature infrared detectors

September 25, 2016
Author(s)
Ivan Ryger, Michelle S. Stephens, John H. Lehman, Matthew T. Spidell, Malcolm G. White, Nathan A. Tomlin, Dave Harber, Peter Lobotka
An absolute electrical substitution radiometer is a way to ensure highly accurate and stable measurement of optical power in a wide range of optical wavelengths. Its sensitivity is mainly determined by the temperature stability of the equithermal bath and

Terahertz laser power measurement comparison

September 5, 2016
Author(s)
John H. Lehman, Malcolm G. White, Andreas Steiger, Ralf Mueller, Alberto R. Oliva, Yuqiang Deng, Qing Sun
Abstract: A comparison of terahertz (THz) laser power measurements was undertaken among three national metrology institutes. At two THz frequencies, 2.52 THz (119 µm) and 0.762 THz (394 µm), a power level of approximately 3 mW was compared at one place at

Portable high-accuracy non-absorbing laser power measurement at kilowatt levels by means of radiation pressure

February 16, 2016
Author(s)
Paul A. Williams, Joshua A. Hadler, Frank C. Maring, Robert Lee, Kyle A. Rogers, Brian J. Simonds, Matthew T. Spidell, Ari D. Feldman, John H. Lehman
We describe a unique optical power meter which measures the radiation pressure to accurately determine a laser’s optical power output. This approach traces its calibration of the optical Watt to the kilogram. Our power meter is designed for high-accuracy

Morphological and Electrical Characterization of MWCNT Papers and Pellets

December 27, 2015
Author(s)
Elisabeth Mansfield, Ari D. Feldman, Ann C. Chiaramonti Debay, John H. Lehman, Alexandra E. Curtin
Six types of multiwall carbon nanotube soot were obtained and prepared into buckypapers by pellet pressing and by filtration into a paper. These samples were evaluated with respect to thickness, compressibility and electrical conductivity. DC conductivity

Atomic Clock with 1x10 -18 Room-Temperature Blackbody Stark Uncertainty

December 31, 2014
Author(s)
Kyle P. Beloy, Nathan M. Hinkley, Nate B. Phillips, Jeffrey A. Sherman, Marco Schioppo, John H. Lehman, Ari D. Feldman, Leonard M. Hanssen, Christopher W. Oates, Andrew D. Ludlow
The Stark shift due to blackbody radiation (BBR) is a key factor limiting the performance of many atomic frequency standards, with the BBR environment inside the clock apparatus being difficult to characterize at a high level of precision. Here we

Progress toward Radiation-Pressure-Based Measurement of High-Power Laser Emission - Under Policy Review

October 6, 2014
Author(s)
Paul A. Williams, Joshua A. Hadler, Daniel King, Robert Lee, Frank C. Maring, Gordon A. Shaw, Nathan A. Tomlin, John H. Lehman, Marla L. Dowell
We present an overview of our efforts toward using optical radiation pressure as a means to measure optical power from high-power lasers. Early results with measurements ranging from tens of watts to 92 kW prove the concept, but validation uncertainties

A CW calibrated laser pulse energy meter for the range 1 pJ to 100mJ

May 13, 2014
Author(s)
Malcolm G. White, Rodney W. Leonhardt, David J. Livigni, John H. Lehman
We describe the use of a silicon photodiode trap detector and digital storage oscilloscope as an absolute laser pulse energy meter, capable of repetition rates of 85 Hz and 5% uncertainty (k = 2). The maximum repetition rate is limited by the decay time of

EVALUATING THERMAL DAMAGE RESISTANCE OF GRAPHENE/CARBON NANOTUBE HYBRID COMPOSITE COATINGS

March 7, 2014
Author(s)
Lamuel David, Ari D. Feldman, Elisabeth Mansfield, John H. Lehman, Gurpreet Singh
Carbon nanotubes and graphene are known to exhibit some exceptional thermal (K~2000 to 4400 W.m-1K-1at 300K) and optical properties. Here, we demonstrate preparation and testing of multiwalled carbon nanotubes and chemically modified graphene-composite

Use of radiation pressure for measurement of high-power laser emission

October 15, 2013
Author(s)
Paul A. Williams, Joshua A. Hadler, Robert Lee, Frank Maring, John H. Lehman
We demonstrate a paradigm in absolute laser radiometry where a laser beam's power can be measured from its radiation pressure. Using an off-the-shelf high-accuracy mass scale and a 500 W Yb-doped fiber laser and a 92 kW CO2 laser, we show preliminary