针对ICF系统要求, 提出了一种基于统计理论的大口径光学元件功率谱密度测量方法。该方法将大口径波前划分成足够多个子区域, 分别求得每个子区域波前的功率谱密度, 根据统计理论可将大口径波前功率谱密度表示为各个子区域波前功率谱密度的加权平均, 其权重因子是各子区域对应的面积。模拟计算和实验结果验证了统计法测量的有效性, 并表明当子区域个数大于等于8×8时, 统计法测量和子孔径拼接测量得到的功率谱密度吻合较好。统计法测量对平台移动精度和环境稳定性要求不高, 可应用于大口径光学元件功率谱密度的过程检测。

According to the requirement of ICF, a method based on statistical theory has been proposed to measure the power spectrum density(PSD) of large aperture optical components. The method breaks the large-aperture wavefront into small regions, and obtains the PSD of the large-aperture wavefront by weighted averaging of the PSDs of the regions, where the weight factor is each region’s area. Simulation and experiment demonstrate the effectiveness of the proposed method. They also show that, the obtained PSDs of the large-aperture wavefront by statistical method and sub-aperture stitching method fit well, when the number of small regions is no less than 8×8. The statistical method is not sensitive to translation stage’s errors and environment instabilities, thus it is appropriate for PSD measurement during the process of optical fabrication.