Simultaneous measurement of retardance and fast axis angle of a quarter-wave plate using one photoelastic modulator

摘要

A method for simultaneous measurement of the retardance and the fast axis angle of quarter-wave plate using one photoelastic modulator is presented. A laser beam passes through a polarizer, a photoelastic modulator, the quarter-wave plate to be measured, and an analyzer to be detected. Before and after the quarter-wave plate is rotated 45 deg at any initial fast axis direction, two detection signals are obtained to resolve simultaneously the retardance and the fast axis angle. In experiments, a quarter-wave plate was measured with fast axis angles from -89 deg to 90 deg. The average and the standard deviation of the retardances at different fast axis directions are respectively 89.50 deg and 0.17 deg. The maximum measurement deviation of the fast axis angle is 0.5 deg. The usefulness of the method is verified.