In-situ measurement of mirror deformation using dual Fabry–Pérot cavities for optical pressure standard

Abstract

An optical pressure measurement system using Fabry–Pérot (FP) cavities are being developed in several national metrology institutes as a future pressure standard. One of the challenges in these research endeavors is the deformation of the FP cavity. The purpose of this study is to evaluate mirror deformation in FP cavities constructed using different materials for the spacer and mirrors, both by simulation and experiment. Experimental and finite element method (FEM) simulation results are in broad agreement. The mirror deformation amount can be determined using the dual cavity method without using the nominal values of material and without depending on conventional pressure standards. Our results suggest that the dual cavity method as well as FEM simulation should be adopted for situations in which the mirror deformation is large and/or high accuracy is required. The results of this study contribute to the development of the primary pressure standard using FP cavities.