Vacuum measurement using total-internal-reflection heterodyne interferometry

Abstract

Based on the effect that the phase difference between s- and p-polarizations at the total-internal-reflection is changed with the variation of the air refractive index, which is related to the air pressure, a new optical method for measuring the air pressure of a vacuum cavity is proposed. From the experimental curve of the phase difference variation measured by the heterodyne interferometry and the calibrated pressure measurement of a vacuum cavity, an empirical formula is derived. With this empirical formula, the mensurable range of this new optical method is 760 to 0.1 torr. (C) 1999 Elsevier Science Inc. All rights reserved.