Towards medium vacuum measurements using an optical pressure standard

Optical pressure standards (OPS) using Fabry-Perot (FP) cavities can measure a wide pressure range with high accuracy. National metrology institute of Japan (NMIJ) is developing an OPS for a pressure range of 1 Pa–100 kPa. In this study, the target uncertainty of the OPS, its current specifications in the range from 40 kPa to 120 kPa, and the challenges for measuring below 100 Pa are reported. In addition, the methods for solving the challenges to achieve the target uncertainty is considered.