Quick and simultaneous measurement of Phase retardation and azimuth of arbitrary wave plate based on phase compensation and dual-frequency laser heterodyne interferometry

Abstract

In this paper, a simple, quick and ingenious wave plate (WP) measurement method based on phase compensation and dual-frequency laser heterodyne interferometry is proposed. A key rotatable half wave plate (HWP) is used for modulating the phase of the measurement signal and compensate it to the maximum and minimum values in sequence. By only measuring the extreme values of phase difference change between the measurement and the reference signal as well as fast axis azimuth of the HWP, the phase retardation and fast axis azimuth of arbitrary WP can be derived simultaneously and quickly. The phase retardation’s measurement avoids the influence of the azimuth positioning accuracy of optical components that typically exists in many methods. The signal processing adopts phase detection means, which means higher accuracy than that by intensity detection means. The reference and measurement paths both contain p and s polarization components, so the system has the common optical path property, which means good stability. Error analysis shows the measurement uncertainty of the phase retardation is about 3.2′, and that of the fast axis azimuth is about 5'' (arcsecond) under existing experimental conditions. The experimental comparison results show good agreement with those by other two methods.