为了定量研究相位差波前探测技术(phase diversity technique, PD)对波前探测和图像重建的精度, 本文分别进行了数值模拟以及相关实验。数值模拟中采用了均方根(root-mean-square, RMS)分别为0.1λ~0.5λ的五组随机畸变波前, 获得其退化的焦面图像和相应的离焦图像信息, 利用PD技术对其进行波前探测和图像重建, 波前探测的残余误差RMS值均达到了10－5λ水平, 重建图像在分辨率和对比度上有明显提升。搭建了基于液晶空间光调制器的实验系统, 利用液晶空间光调制器来定量施加随机的波前像差, 可以有效解决湍流屏数据难以量化的问题。同样将PD技术应用于本实验所采集到的退化焦面图像和相应离焦图像, 对于RMS值为0.306λ的随机波前像差, 探测波前的残余误差为0091λ, 图像重建结果与模拟结果高度一致, 本文列举并分析了可能造成实验误差的多种因素, 同时为该技术应用于液晶系统积累了技术基础。

In order to study phase diversity (PD) technique quantitatively, numerical simulations and experiments has been performed. In numerical simulations, 0.1λ~0.5λ root-mean-square (RMS) random phase aberrations are used to investigate the PD technique from images degraded by these random phase aberrations. Root-mean-square errors (RMSE) of phase aberrations detected by PD is less than 10－5λ, and the reconstructed images become much better than the degraded focus-plane images.An experimental system based on Liquid Crystal Spatial Light Modulator (LC-SLM) is established,and the problem of lacking quantitative data for atmospheric turbulence phase screen can be solved effectively. RMSE of the phase aberrations of the experimental data is0.091λ for which the RMS of original phase aberrations is 0.306λ.The estimated wave-front is very similar to original phase aberrations. The experimental and simulation results agree well.Several reasons are also analyzed which could result in experimental error, and this work also gets technical experiences for the application of PD technique in liquid crystal adaptive system in future.