光学表面非均匀中频误差的评价与修正

Evaluation and modification of nonuniform mid-spatial frequencyerror in optic surface

摘要: 针对光学元件使用过程中中频误差将导致光学元件的激光破坏这一问题，提出一种中频误差突出频率提取方法。采用基于统计学的多样本数据处理，对于每一种采样方向都可以得到数个较为突出的不合格频率。利用这些频率进行确定性加工后，在特定方向，空间频率0.044 1 mm-1，0.085 8 mm-1，0.041 7 mm-1所出现的不合格次数分别降至加工前的23.9%，18.3%，29.2%，而整体中频误差减少至50.1%。结果表明，此方法降低了由光学表面中频误差方向性与局部性引起的不确定性。

Abstract: Mid-spatial frequency(MSF) wavefront error leads to laser damage during the use of optics. Therefore the accurate evaluation and modification are necessary in manufacture. A unique way based on multi-sample analysis was proposed for error frequency. Several outstanding frequencies were found in every sampling direction. After eliminating with the help of these frequencies, along with certain sample direction, unqualified frequency errors in 0.041 7 mm-1, 0.085 8 mm-1,0.041 7 mm-1 were down to 23.9%, 18.3%, 29.2%,respectively, while the MSF in whole optic surface decreased to half. According to the method above, the uncertainty caused by directionality and regionality of MSF in optic surface can be restrained.