Real-time measurement of retardation and fast axis azimuth for wave plates

Abstract

Real-time measurement of retardation and fast axis azimuth of wave plates is proposed. The light emitted from the laser passes through a circular polarizer and the sample successively. Then the beam is diffracted to three sub-beams by a grating. One sub-beam passes through a standard quarter-wave plate and then is split and analyzed by a Wollaston prism. The other two sub-beams are all directly split and analyzed by Wollaston prisms. Six intensities are simultaneously detected to calculate the retardation and the fast axis azimuth. Experiments show that for the quarter-wave plate the average and standard deviation of the retardation are 89.78° and 0.14°, respectively, and the maximum deviation of the fast axis azimuth is 0.6°; for the eighth-wave plate, the average and standard deviation of the retardation are 45.15° and 0.15°, respectively, and the maximum deviation of the fast axis azimuth is 0.53.