Imaging spectropolarimetric detection using acousto-optic tunable filter and liquid crystal variable retarder

Compared with the conventional system of secondary imaging spectrum, the full polarization imaging spectrum of acoustooptic tunable filter (AOTF) based on the wavelength scanning of a type of AOTF and phase modulation of the double liquid crystal variable retarder (LCVR) has many advantages, for example, the larger limiting aperture,high light utilization and the electronic tuning of full system. Besides, it can meet the small incident angle of AOTF and LCVR so as to greatly improve the spectral measurement precision and polarization measurement precision. The experiment results show that its relative error can be reduced an order of magnitude by using the revised equation of the wavelength 0 and the driving frequency fa to measure the spectrum. Through calculation, we can calculate all the parameters S=S0 S1 S2 S3T of Stokes in only 4 groups of phase delay and 4 intensity images. When considering the incident angle, the maximum relative error of the degree of polarization, the degree of linear polarization, the degree of circular polarization and the degree of angle polarization respectively reduced about 0.306%,0.130%,10.96% and 3.783% than that we only considered the light vertical incidence. This can provide a theoretical basis in order to further improve the measurement precision.