抛光表面的亚表层损伤检测方法研究

A Novel Method for Subsurface Damage Measurement of Optical Components

光学元件磨削加工引入的亚表面损伤威胁着光学元件的使用性能及寿命,成为现阶段高能激光发展的瓶颈问题,特别是抛光表面光学元件的亚表面损伤检测已成为光学元件制造行业的研究热点和难点.本文结合光学共聚焦成像、层析技术、显微光学、光学散射以及微弱信号处理等技术,给出了基于光学共焦层析显微成像的光学元件亚表面损伤检测方法.分析了不同针孔大小对测量准确度的影响,并首次给出了亚表面损伤的纵向截面分布图.与腐蚀法比较结果显示:针对自行加工的同一片K9玻璃,采用本文提出的方法测得的亚表面损伤深度45μm左右;采用化学腐蚀处理技术,对光学元件逐层刻蚀,观察得到的亚表面损伤深度50～55μm.两者基本一致,进一步验证了本文采用的方法可以实现对光学元件亚表面损伤的定量、非破坏检测.

Subsurface damages produced in grinding process will influence optical performance and lifetime of optical elements.The testing for subsurface damage of polished surface is research hot and difficult point now.Combination of confocal image,tomography technology,microscope optics,optical scatter and weak signal processing,a novel method based on laser confocal microscope tomography is proposed.The effects of different sizes of pinhole on measure accuracy are analyzed,and the cross section microstructure picture of the subsurface damage sample is given.The subsurface damage depth is about 45 μm with this novel method.For the same K9 glass,the subsurface damage depth is about 50～55 μm with the chemical corrosion treatment technology.The measurement results are basically consistent.Comparison with the destructive etching method shows that this novel method is good for polished surface in quantitative and non-destructive.