Recent advances in Fabry-Perot-based refractometry utilizing gas modulation for assessment of pressure

M. Zelan, I. Silander, C. Forssén, J. Zakrisson, O. Axner


Gas modulation refractometry (GAMOR) is a methodology that can mitigate the influence of fluctuations and drifts in Fabry-Pérot cavity–based refractometry. This paper presents a thorough description of its principles, what it enables, and its applicability. An overview of the latest results is presented, including the realization of a system based upon a cavity spacer made of Invar that allows for detection of N2 with sub-ppm precision, and a characterization procedure that allows for assessment of N2 with an accuracy at low-ppm levels.

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