Working equation for a Fabry-Perot cavity based optical pressure standard

Yuanchao Yang, Patrick F. Egan, Tom Rubin

Abstract

From basics of Fabry-Perot (FP) resonator and roundtrip phase, a complete working equation for a FP cavity based optical pressure standard (OPS) is derived and presented which includes corrections of reflection phase-shift, diffraction and pressure-induced distortion. The correction from diffraction, i.e. Gouy phase, is negligible. To operate an OPS as a primary standard, two unknown parameters, i.e. mirror dispersion coefficient ϵ_α and pressure distortion coefficient d_m, in the working equation should be determined independently. Methods to determine ϵ_α and d_m are described and applied to an OPS developed at the National Institute of Metrology (NIM), China. Thermodynamic effect observed in the determination of d_m is also discussed.

Keywords

Fabry-Perot; refractometry; fixed-length; optical cavity; force-balanced; piston gauge; optical pressure; standard

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IMEKO-TC16-2023-09.pdf

DOI

10.21014/tc16-2023.09

IMEKO TC

TC16 - Pressure and Vacuum Measurement

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