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Publication Citation: Absolute refractometry of dry gas to ±3 parts in 109

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Author(s): Patrick F. Egan; Jack A. Stone Jr.;
Title: Absolute refractometry of dry gas to ±3 parts in 109
Published: June 20, 2011
Abstract: 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 < 3 × 10-9 (coverage factor k = 2. The main contribution to this uncertainty is how well vacuum-to-atmosphere compression effects (length variation) in the cavities can be corrected for. This paper describes the technique and reports reference values for the refractive index of nitrogen and argon gases at 100 kPa and 20 °C with an expanded uncertainty of < 7 × 10-9 (coverage factor k{\I} = 2), with the largest part of this uncertainty coming from the pressure and temperature measurement.
Citation: Applied Optics
Volume: 50
Issue: 19
Pages: pp. 3076 - 3086
Keywords: Metrology, Fabry-Perot, Refraction, Laser stabilization
Research Areas: Dimensional Metrology, Optical Metrology
DOI:  (Note: May link to a non-U.S. Government webpage)
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