U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: John H. Lehman (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 311

Application of Voltage Controlled Crystal Oscillators to DC Voltage Reference Validation

April 8, 2025
Author(s)
Matthew Spidell, Malcolm White, Alan Jaffe, John Lehman, Gaylon Partain
DC voltage references are typically based on calibrated Zener Diodes which are subject to drift and therefore require periodic recalibration against a Primary Standard. Since it is preferable to maintain constant power to such references, the shipping and

A proposal for three categories of units within the SI

April 29, 2024
Author(s)
John Lehman, Alan Migdall, Julia Scherschligt
In this letter we examine the organization of the traditional base units and defining constants established in the 2019 redefinition of the international system of units (SI). For the next redefinition of the SI, which will accompany the anticipated

Multi-kilowatt cw laser power measurement comparison between NMI standards

February 14, 2024
Author(s)
Kyle Rogers, Paul A. Williams, John H. Lehman, Marco Lopez, Marcel Pastuschek, Holger Lecher, Stefan Kueck
We present here the first comparison between National Metrology Institutes (NMIs) of high accuracy continuous wave (cw) optical power measurements in the kilowatt regime. The National Institute of Standards and Technology (NIST) performed measurements with

BABAR-ERI: Black Array of Broadband Absolute Radiometers - Earth Radiation Imager

September 22, 2023
Author(s)
Chris Yung, Cameron Straatsma, Nathan Tomlin, David Harber, Odele Coddington, John H. Lehman, Michelle Stephens
BABAR-ERI is being developed for a CubeSat capable of imaging the Earth's outgoing longwave radiation with a 1 km ground sample distance (GSD) using a push-broom imager. The detector is a silicon micromachined 32-pixel linear array of electrical

High-Power Radiation-Pressure-based Laser Metrology Using an Electrostatic Force Balance

September 11, 2023
Author(s)
Brian Simonds, Kyle Rogers, Sven Schulze, David Newell, Gordon Shaw, John Lehman, Paul A. Williams
A primary standard electrostatic force balance has been integrated into a multiple-reflection radiation pressure-based laser power meter capable of measuring kilowatts of optical power. We present optical power data at 0.1 kW, 1 kW, 2 kW, and 5 kW with the

Enhancement of Optical Absorption by Oxygen Plasma Treatment in Carbon Nanotube-based Black Paint Coating

July 5, 2023
Author(s)
Atasi Dan, Joel Rutkowski, Patrick McArdle, Erica Freire Antunes, Nathan Tomlin, Malcolm White, Michelle Stephens, John H. Lehman
Effect of oxygen (O2) plasma treatment on reflectance properties and surface morphology of CNT-based paint was investigated. We demonstrate a specular reflectance less than 0.10% and hemispherical reflectance less than 2.5% throughout the UV-Vis-NIR range.

Radiation Pressure-based Laser Metrology Implementing an Electrostatic Force Balance

December 12, 2022
Author(s)
Brian Simonds, Kyle Rogers, Sven Schulze, David Newell, Gordon Shaw, Paul A. Williams, John Lehman
A primary standard force sensor and laser power meter are combined to achieve laser power traceability to Planck's constant by means of radiation pressure. We assess the statistical uncertainty for measurements of 1 kW, 2 kW, and 5 kW using an

Single Photon Detectors and Metrology

October 26, 2022
Author(s)
Sonia Buckley, Michelle Stephens, John H. Lehman
For quantum applications, it is important to generate quantum states of light and detect them with extremely high efficiency. For future applications, it also important to do this at scale. This presents many engineering and metrology challenges. This

Extremely broadband calibrated bolometers and microbolometer arrays for Earth radiation budget measurements

September 30, 2022
Author(s)
Michelle Stephens, Chris Yung, Nathan Tomlin, Dave Harber, Cameron Straatsma, Atasi Dan, Erica Freire Antunes, Peter Pilewskie, Odele Coddington, John H. Lehman
The Earth radiation budget, a 40-year data record of the balance between solar radiation reaching the Earth and the amount absorbed, reflected, and emitted from the Earth, is a key climate record for determining whether the Earth is warming or cooling. The

Generalized Electrical Substitution Methods and Detectors for Absolute Optical Power Measurements

June 17, 2022
Author(s)
Solomon I. Woods, Jorge Neira, James E. Proctor, Joseph P. Rice, Nathan Tomlin, Malcolm White, Michelle Stephens, John H. Lehman
We have developed generalized methods for electrical substitution optical measurements, as well as cryogenic detectors which can be used to implement them. The new methods enable measurement of arbitrary periodic waveforms by an electrical substitution

Absolute radiation pressure detector using a diamagnetically levitating test mass

October 28, 2021
Author(s)
Anna Vaskuri, Daniel Rahn, Paul A. Williams, John H. Lehman
We have developed an absolute radiometer to measure laser power by means of radiation pressure in a closed control-loop configuration using diamagnetically levitated pyrolytic graphite as the soft spring and gravity as a contactless restoring force. Our

High-accuracy room temperature planar absolute radiometer based on vertically aligned carbon nanotubes

July 1, 2021
Author(s)
Anna Vaskuri, Michelle Stephens, Nathan Tomlin, Matthew Spidell, Chris Yung, Andrew Walowitz, Cameron Straatsma, David Harber, John H. Lehman
We have developed a Planar Absolute Radiometer for Room Temperature (PARRoT) that will replace the legacy C-series calorimeter as the free-space continuous-wave laser power detector standard at the National Institute of Standards and Technology (NIST)

Room temperature Laser Power Standard Using a Microfabricated, Electrical Substitution Bolometer

February 18, 2021
Author(s)

Michelle Stephens, Christopher Yung, Nathan Tomlin, Anna Vaskuri, Ivan Ryger, Matthew Spidell, Malcolm G. White, Thomas Jenkins, Jennifer Landry, Tesfatsion Sereke, John Lehman

The design and performance of a room temperature electrical substitution radiometer for use as an absolute standard for measuring continuous-wave laser power over a wide range of wavelengths, beam diameters and powers is described. The standard achieves an