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Search Publications by: Patrick Egan (Fed)

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Displaying 51 - 60 of 60

Absolute refractometry of dry gas to +-3 parts in 10 9

June 20, 2011
Author(s)
Patrick F. Egan, Jack A. Stone Jr.
We present a method of measuring the refractive index of dry gases absolutely at 632.8 nm wavelength using a Fabry-Perot cavity with an expanded uncertainty of -9 (coverage factor k = 2. The main contribution to this uncertainty is how well vacuum-to

An Optical Frequency Comb Tied to GPS for Laser Frequency/Wavelength Calibration

November 1, 2010
Author(s)
Jack A. Stone Jr., Patrick F. Egan
Optical frequency combs can be employed over a broad spectral range to calibrate laser frequency or vacuum wavelength. This article describes procedures and techniques utilized in the Precision Engineering Division of NIST (National Institute of Standards

Temperature stabilization system with millikelvin gradients for refractometry

July 25, 2010
Author(s)
Patrick F. Egan, Jack A. Stone Jr.
Refractometry of air is a central problem for interferometer-based dimensional measurements. Refractometry at the 10^{-9} level is only valid if air temperature gradients are controlled at the millikelvin level. Very precise tests of second-generation NIST

Calibrating Laser Vacuum Wavelength With a GPS-Based Optical Frequency Comb

May 15, 2007
Author(s)
Jack A. Stone Jr., Liang Lu, Patrick F. Egan
The Global Positioning System (GPS) can deliver an exceptionally accurate frequency standard to any point in the world. When we use the GPS signal to control an optical frequency comb, the comb+GPS system provides laser light with well-known frequencies