泰曼-格林干涉仪测量液晶空间光调制器的相位调制特性

为了评价美同BNS公司反射式256 pixel×256 pixel纯相位液品空间光调制器(LC SLM)的性能,提出利用泰曼-格林干涉仪对相位调制特性进行干涉测量.实验结果表明,液晶空间光调制器的相化随灰度呈非线性分布,利用反插值法建立线性查找表,校正了器件的非线性.非线性度由原来的17.23%减小到2.85%;中心与边缘的相位调制,在同一灰度级最大相位差达到0.22π,中心相位调制均方根误差是边缘的4倍,说明该器件存在相位调制的不均匀性,中心相位误差较大,在波前控制中应给予校正.

Phase Modulation of Liquid Crystal Spatial Light Modulator Measured by a Twyman-Green Interferometer

In order to evaluate the performance of a reflective 256 pixel×256 pixel phase-only liquid crystal spatial light modulator (LC SLM) from American BNS Company, interference measurements are proposed on the characteristics of phase modulation using a Twyman-Green interferometer. Experimental results indicate that the relation between phase and gray level is nonlinear. A linear look up table is established by inverse interpolation to correct the nonlinearity for this device. The nonlinearity decreases to 2.85% from 17.23%. The phase difference between the centre and the edge is 0.22π on the equal gray level and the root-mean-square error of phase modulation for the centre is 4 times of that for the edge, which shows the phase modulation for this device is nonuniform and the phase error for the centre should be corrected in wave-front control application.