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Search Publications by: Paul A. Williams (Fed)

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Displaying 26 - 50 of 111

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

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

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

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

Absolute spectroscopy of N2O near 4.5 um with a comb-calibrated, frequency-swept quantum cascade laser spectrometer

January 14, 2013
Author(s)
Kevin O. Knabe, Paul A. Williams, Fabrizio R. Giorgetta, Michael Radunsky, Chris Armacost, Sam Crivello, Nathan R. Newbury
We present absolute line center frequencies for 24 fundamental nu-3 ro-vibrational P-branch transitions near 4.5 um in N2O with an absolute frequency uncertainty of 800 kHz. The spectra were acquired with a swept laser spectrometer consisting of an

Frequency characterization of a swept and fixed-wavelength external-cavity quantum cascade laser by use of a frequency comb

May 21, 2012
Author(s)
Kevin O. Knabe, Paul A. Williams, Fabrizio R. Giorgetta, Chris Armacost, Michael Radunsky, Nathan R. Newbury
The instantaneous optical frequency of an external-cavity quantum cascade laser (QCL) is characterized by comparison to a near-infrared frequency comb. Fluctuations in the instantaneous optical frequency are analyzed to determine the frequency noise power

Comb-assisted swept laser spectroscopy with a mode-hop free tunable external cavity QCL

May 1, 2012
Author(s)
Kevin O. Knabe, Fabrizio R. Giorgetta, Nathan R. Newbury, Chris Armacost, Michael Radunsky, Sam Crivello, Timothy Day, Paul A. Williams
We demonstrate sub-MHz spectral resolution of N 2O absorption spectra acquired with a swept external-cavity quantum cascade laser (QCL) over 0.87 THz. The QCL frequency is monitored by sum -frequency generation with an optical fiber frequency comb.

Broad bandwidth trace gas and standoff detection with infrared frequency comb sources

March 11, 2012
Author(s)
Nathan R. Newbury, Alexander M. Zolot, Esther Baumann, Fabrizio R. Giorgetta, Florian B. Adler, Ian R. Coddington, Kevin O. Knabe, Lora L. Nugent-Glandorf, Paul A. Williams, Scott A. Diddams, Tyler W. Neely
An optical frequency comb based on the output of a mode-locked femtosecond laser can be used in spectroscopic studies and sensing applications. The broad array of frequency modes simultaneously provides high spectral resolution and broad wavelength

Long distance frequency transfer through an optical carrier

August 2, 2009
Author(s)
Paul A. Williams
Fiber optic networks are an attractive means for the remote distribution of highly stable frequencies from optical clocks. The highest performance is achieved by use of the frequency of the optical carrier itself as the transfer frequency. We will review

Word-synchronous linear optical sampling of 40 Gb/s QPSK signals

March 20, 2009
Author(s)
Tasshi Dennis, Paul A. Williams, Ian R. Coddington, Nathan R. Newbury
We demonstrate word-synchronous measurements of QPSK format 40 Gb/s PRBS signals using linear optical sampling with a precision time-base, which allows us to average waveforms and distinguish between signal distortion and noise in eye diagrams.

Coherent measurements with fiber-laser frequency combs

February 2, 2009
Author(s)
Nathan R. Newbury, Ian R. Coddington, Tasshi Dennis, William C. Swann, Paul A. Williams
The coherent and broad spectral output of fiber-laser frequency combs can be exploited for a variety of high-resolution measurements outside of conventional frequency metrology. We will discuss recent measurements in spectroscopy, ranging, and

Bilateral comparison on polarization mode dispersion between KRISS and NIST

October 10, 2008
Author(s)
Seung-kwan Kim, Paul A. Williams
We made an international bilateral comparison on polarization mode dispersion between KRISS and NIST. Three mode-coupled artifacts were used for comparison. The average values of differential group delay measured by both institutes agreed well within their