液晶相位调制型声光成像光谱偏振测量研究

新型的声光可调滤波器和双液晶相位可调延迟器相结合的一次成像光谱偏振系统与传统的二次成像光谱系统相比，不仅具有通光孔径大、光利用率高和全系统电调谐等优点，而且还能同时满足AOTF和LCVR的小角度入射，大大提高了光谱测量精度和偏振测量精度。通过实验计算，用拟合修正后的波长0和驱动频率fa关系式进行光谱测量，其相对误差值比用理论公式进行测量时减小约一个数量级。并且只需4组相位延迟量和4幅强度图即可求出全部的斯托克斯Stokes参量。理论分析了当系统考虑入射角度时，其偏振度、线偏振度、圆偏振度和角偏振度的最大相对误差值比只考虑光垂直入射时分别减少约0.306%、0.130%、10.96%和3.783%，为进一步提高系统的测量精度提供了理论基础。

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 S3]T 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.