Heterodyne interferometry for the characterization of optical anisotropic materials

In optical measurement field, the heterodyne interferometric technology is an important technique for precise measurements. The electro-optic materials such as liquid crystals and Pockels cell are used as the polarization modulators to generate heterodyne signals in the polariscope. The polariscope with heterodyne-based configuration is applied for the characterization of optical anisotropic materials such as the glucose concentration, the principal axis angle and retardation of linear birefringence material. The cell gap, twist angle, and azimuth angle of liquid crystal cells are also characterized by the proposed technology. The advantage of the heterodyne polarimeter introduces high-sensitivity on intensity and phase detections, and the multiple parameters of birefringence materials could be extracted through proper signal analysis algorithm. The operation principle and the way to achieve 2- dimentional measurement are fully discussed in the chapter.