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Search Publications by: Marla L. Dowell (Fed)

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Displaying 26 - 50 of 99

Comparison of absolute measurements of laser power using next generation NIST high power radiometer and Air Force high power calorimeter

June 8, 2011
Author(s)
Marla L. Dowell, Christopher L. Cromer, Xiaoyu X. Li, John Bagford, Dan Seibert, John Eric, David Cooper, Steven Comisford, Ernie Cromwell, Richard Bowling
We report comparisons of laser power measurements between the new NIST radiometer, also known as the BB Prime, and the current Air Force standards, known as the BB calorimeter. [1] These measurements were performed using high power laser sources in the Air

Bilateral comparison of power measurement standards for KrF lasers between PTB and NIST

May 2, 2010
Author(s)
Marla L. Dowell, Christopher L. Cromer, Darryl A. Keenan, Stefan Kuck, Friedhelm Brandt
We report results of the first bilateral laser power comparison for 248-nm KrF excimer lasers accomplished by the National Metrology Institutes of Germany (Physikalisch-Technische Bundesanstalt, PTB) and of the United States of America (National Institute

Reflective attenuators for high energy laser measurements

March 14, 2010
Author(s)
John H. Lehman, David J. Livigni, Christopher L. Cromer, Xiaoyu X. Li, Marla L. Dowell
A high-energy laser attenuator in the range of 250 mJ (20 nsec pulse width, 10 Hz repetition rate, 1064 nm, 1574 nm wavelengths) is described. The optical elements that constitute the attenuator are mirrors with relatively low reflectance, oriented at 45°

Uncertainty calculation for spectral-responsivity measurements

September 1, 2009
Author(s)
John H. Lehman, Chih-Ming Wang, Marla L. Dowell, Joshua A. Hadler
This paper discusses a procedure for measuring the absolute spectral responsivity of optical-fiber power meters and computation of the calibration uncertainty. The procedure reconciles measurement results associated with a monochromator-based measurement

UV pulse response nonlinearity of two Si photodiodes

October 30, 2008
Author(s)
Shao Yang, Darryl A. Keenan, Marla L. Dowell
We measured the pulse response nonlinearity of two silicon photodiodes at 193 and 248 nm with different measurement conditions. We found large and different nonlinearities. We discuss the cause of the nonlinear features.

Choosing the right detector for laser power and energy measurements

October 1, 2008
Author(s)
Marla L. Dowell
You may not realize the importance of good laser metrology and its many pitfalls until you realize how much of today’s commonplace conveniences – from long distance communications to LASIK (laser-assisted in situ keratomileusis) to state-of-the-art cutting

High power laser calibrations at NIST

September 1, 2008
Author(s)
Xiaoyu X. Li, Joshua A. Hadler, Christopher L. Cromer, John H. Lehman, Marla L. Dowell
This document describes the calibration service for the responsivity of laser power meters and detectors used with continuous wave high power lasers at laser wavelengths of 1.06 and 10.6 micrometers. An overview of the calibration procedures, measurement

Reflective attenuator for high energy laser measurements

June 20, 2008
Author(s)
John H. Lehman, David J. Livigni, Xiaoyu X. Li, Christopher L. Cromer, Marla L. Dowell
A high-energy laser attenuator in the range of 250 mJ (20 nsec pulse width, 10 Hz repetition rate, 1064 nm wavelength) is described. The optical elements which constitute the attenuator are mirrors with relatively low reflectance, oriented at 45° angle of

Biophotonic tools in cell and tissue diagnostics

May 1, 2007
Author(s)
Michael Brownstein, Robert A. Hoffman, Richard Levenson, Thomas E. Milner, Marla L. Dowell, Paul A. Williams, Grady S. White, Adolfas Gaigalas, Jeeseong C. Hwang
In order to maintain the rapid advance of biophotonics in the U.S. and to enhance our competitiveness worldwide, key measurement tools must be in place. As a part of a wide-reaching effort to improve the U.S. technology base, the National Institute of

Review of ultraviolet and high power laser measurement standards at NIST

October 25, 2006
Author(s)
John H. Lehman, Christopher L. Cromer, Shao Yang, Marla L. Dowell
High accuracy laser radiometry is on the verge of growth and improvements just as new laser technologies are evolving. Our present tasks are directed toward anticipating and meeting the measurement needs in two areas; higher power and shorter wavelengths

The Next Generation of Laser Radiometry at NIST

February 27, 2006
Author(s)
John H. Lehman, Christopher L. Cromer, Marla L. Dowell
High accuracy laser radiometry is on the verge of significant improvements just as new laser technologies are evolving. Our present tasks are directed toward anticipating and meeting the measurement needs in two areas; higher power and shorter wavelengths

Nonlinearity of Response of Silicon Photodiodes at 193 nm

May 11, 2005
Author(s)
Shao Yang, Darryl A. Keenan, Marla L. Dowell
We have developed a measurement system based on a correlation method to characterize the nonlinearity response of silicon photodiodes to pulsed-laser radiation at 193 nm. The method compares the pulse response of the device under test with that of a