Development of optical barometer and its performance evaluation in low vacuum

Abstract

Gas refractivity is proportional to pressure. The refractivity is evaluated from light wavelengths in vacuum and in gas. In this study, we developed an optical barometer using the gas refractometer. Nitrogen gas with high purity and a semiconductor laser with a wavelength of about 633 nm were used. The optical barometer was compared with a calibrated pressure gauge in the pressure range of 10 kPa to 100 kPa. The results agreed within the uncertainty of the calibration of the gauge.