基于偏振显示的液晶空间光调制器相位特性研究

Research on Phase Characteristics of Liquid Crystal Spatial Light Modulator Based on Polarization Display

为了校准液晶空间光调制器,基于偏振显示原理提出一种测量液晶空间光调制器相位调制特性的方法。首先分析液晶空间光调制器对入射线偏振光偏振态的调制特性,然后建立椭圆偏振光经过角向偏振显示器后的长轴方向与液晶空间光调制器相位调制量的理论关系,并搭建测量液晶空间光调制器相位特性的光学系统。结果表明,所用的空间光调制器的最大相位调制量为2.45πrad,在15~210灰度范围内的相位调制曲线近似呈线性分布。最后采用反插值法对相位调制曲线进行线性校正,并生成输入灰度和驱动灰度的查找表,校正后的相位调制曲线与理想线性调制曲线的相关系数可达0.9993。

To calibrate liquid crystal spatial light modulators,a method for measuring their phase modulation characteristics is proposed based on the principle of polarization display.First,the modulation characteristics of the liquid crystal spatial light modulator to the polarization state of the incident polarized light are analyzed.Then,a theoretical relationship is established between the long axis direction of the elliptically polarized light after passing through the azimuthally polarization axis finder and the phase modulation amount of the liquid crystal spatial light modulator.By building an optical system,the phase characteristics of the liquid crystal modulator are measured.The results show that the maximum phase modulation of the spatial light modulator used is 2.45πrad,and the phase modulation curve within the gray scale range of 15 to 210 approximately meets the linear distribution.Finally,the phase modulation curve is linearly corrected by applying inverse interpolation,and a look-up table of the input gray scale and the driving gray scale is generated.The correlation coefficient between the corrected phase modulation curve and the ideal linear modulation curve reached 0.9993.