傅里叶λ/4波片双折射检测方法

摘要

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 .%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.