为了对液晶光学相控阵的相位调制量进行高分辨率、高精度的自动化测量, 采用了傅里叶λ/4波片法, 在常规λ/4波片法的基础上, 结合离散傅里叶变换算法完成数据处理过程, 获得更高的测试精度, 并且对测试环境的振动、噪声具备更好的抑制能力。实验中, 利用微机控制步进电机、CCD等辅助设备, 结合傅里叶λ/4波片法形成自动检测设备。结果表明, 将标准λ/4波片作为测试样品, 测试重复精度小于0.3°; 将自行研制的液晶光学相控阵作为待测样品, 获得了其近场的相位分布, 可看到样品的相位周期性与电极间相位凹陷等情况。

In order to measure the phase modulation of liquid crystal optical phased arrays(LCOPA) automatically with high resolution and high precision, Fourier quarter-wave-plate (FQW) method was adopted. On the basis of the conventional λ/4 wave-plate method, combined with the discrete Fourier transform algorithm to process data, higher accuracy was attained in spite of the influence of vibration and noise in surroundings. In the experiments, automatic test was accomplished with a computer controlling the stepping motor combing accessory devices such as CCD and FQW. The results showed that the repetitive test precision was less than 0.3° taking a standard λ/4 wave-plate as a test sample. The near-field phase distribution for a LCOPA developed by ourselves was obtained and its phase cycle and phase valley between the electrodes was observed.