Measurement of optical rotation as a function of temperature using a common-path heterodyne polarimeter

Abstract

We employ a common-path heterodyne polarimeter to measure the variation of optical rotation (OR) with temperature. A heterodyne beam with two orthogonal polarizations is incident on a sample and a half-wave plate set at an azimuth angle of 22.5°. Any change in the sample's OR results in a large phase shift between the two polarizations. We measure this phase shift using a lock-in amplifier and compare it with a reference signal. Our experimental results show that the OR increases with temperature.