平行平板横向剪切干涉仪波前重建精度的研究

在基于平行平板双光路横向剪切干涉仪中,如果 两个方向的平行平板之间存在角度误差,将会使得 两个方向的剪切干涉图的剪切方向不正交,最终影响波前测量的准确度。本文通过仿真实验 研究了两个方 向平行平板之间不同大小的角度误差对波前重建精度的影响,分析了不同条件下Zernike多 项式系数拟合 精度、重建波前均方根(RMS)及均方根误差(RMSE)与角度误差之间的关系以 及角度误差一定时,重建波前 RMS及RMSE与剪切量之间的关系。研究结果表明,为了提高波前重建精度,要尽量降低两 个平行平板之 间的角度误差,使用更多项Zernike多项式来拟合波前,并且保证剪切量与波 面尺寸比值大于10%。本文的 结论对于平行平板横向剪切干涉仪的装调将会起到一定的指导作用。

Study on wavefront reconstruction accuracy of parallel plate lateral shearing interferometer

For the parallel plate lateral shearing interferometer,if there is an angle error between the parallel plates in the two directions,the shearing interferograms of two directions are not ort hogonal,accuracy of wavefront measurement will be worsened.In order to analyze the influence of the angle err or between the parallel plates on the accuracy of the wavefront measurement,accuracy of wavefront reconstruction is s tudied through simulation experiments,and the relationships among the fitting accuracy of Zernike polynom ial coefficients,the root mean square (RMS) and root mean square error (RMSE) of the reconstructed wavefront an d the angle error of the parallel plate are analyzed.The relationships of the RMS and RMSE of the reconstructed w avefront and the shear are analyzed when the angle error is constant.It is shown that the angle error betw een two parallel plates should be reduced to improve the accuracy of wavefront reconstruction,more Zernike polyno mials should be used to fit the wavefront,and the ratio of shear to wavefront size should be greater than 10%.T he conclusions of this paper will play a guiding role in the installation and adjustment of the parallel plate lat eral shearing interferometer.