光束漂移的莫尔条纹检测原理

针对大气湍流光束漂移，设计了一套使用莫尔条纹进行检测的系统，该系统具有检测微小长度和角度的特点，它是将光束漂移的微小角度借助条纹的方式进行放大。分析大气湍流条件下可能获得的最大条纹宽度，然后将条纹宽度和现有较好的CCD分辨率作比较。在CCD分辨率不足的情况下，采用莫尔条纹细分技术，通过适当的电路，将条纹的光信号转换成电信号，使相位变化转换为脉宽的变化，并在形成的方波中内插高频脉冲，通过测量脉冲数目可进一步实现高倍率细分，从而达到较高的分辨率，理论上系统的检测精度可达到0.025μrad。

Beam wander detected by Moiré fringe

A system that uses Moiré fringe to detect the beam wander caused by atmospheric turbulence is presented. This system features tiny length and angle detection. The tiny angle of the beam wander was detected by using the Moiré fringe and amplified in the mode of fringe.The widest fringe obtained in the atmospheric turbulence was analyzed,and the width of the fringe was compared with the resolution of sophisticated CCD. Moiré fringe subdividing technique was used when the resolution of the CCD was not sufficient. The optical signal of the fringe was converted to the electric signal by a proper circuit,and the phase variation was converted to the pulse-width variation. The high frequency pulse was inserted into the formed square wave and the high-multiplying-power subdivision was attained by measuring the numbers of the pulse. The high resolution can be achieved by this method which can make detection precision of the system reach 0.025 μrad.