Effect of elliptical birefringence on the measurement of the phase retardation of a quartz wave plate by an optical heterodyne polarimeter

The elliptical birefringence of a quartz phase-retardation plate was precisely measured and discussed. A polarized optical heterodyne interferometer with a common path configuration was proposed and set up. It was used to measure the linear phase retardation of λ/4 quartz wave plate, taking the elliptical birefringence into consideration. The ratio of the amplitude of the heterodyned P and S waves versus the azimuth angle of the quartz plate was more sensitive to elliptical birefringence than was the phase retardation. The experimental data, which were well fitted to the theoretical curve, showed evidence of the existence of small elliptical birefringence in the tested λ/4 quartz wave plate. However, the results of the experiment confirm the general belief that the phase difference of the wave plate is not sensitive to the elliptical birefringence effect.