Characterization of manufacturing-induced surface scratches and their effect on laser damage resistance performance of diamond fly-cut KDP crystal
Characterization of manufacturing-induced surface scratches and their effect on laser damage resistance performance of diamond fly-cut KDP crystal
复制标题
制造引起的表面划痕及其对金刚石飞切 KDP 晶体抗激光损伤性能的影响
DOI：
10.1016/j.rinp.2019.102753
复制
发表时间：
2019-12-01
影响因子：
5.3
通讯作者：
Tan, Jiubin
中科院分区：
文献类型：
--
作者：
Cheng, Jian;Yang, Hao;Tan, Jiubin
为了提高KDP晶体在高功率激光系统中的抗激光损伤性能，制造缺陷引起了越来越多的关注。本文对金刚石飞切KDP晶体表面划痕的形貌进行了表征，并从理论和实验上研究了划痕对抗激光损伤性能的影响。结果表明，表面划痕可以通过调制入射激光并产生局部光强来降低激光损伤阈值。诱导的最大光强增强因子(LIEF)取决于划痕的形状和尺寸。源于划痕边缘的衍射效应是导致最强光增强的原因。即使超精密抛光KDP表面的划痕满足当前应用的划痕/挖掘规范，诱导的LIEF也相当高，这表明实际的缺陷尺寸余量应该根据缺陷诱导的LIEF进行修正和指定。通过实验验证了划痕对激光损伤抗力的影响，与模拟结果基本一致。激光损伤部位的形貌进一步证实了划痕在降低LIDT中的作用。为全面评价高功率激光设备中应用的超精密制造光学材料的性能提供了新的视角和指导。
Manufacturing-induced defects have drawn more and more attentions to improve the laser damage resistance performance of KDP crystal applied in high-power laser systems. Here, the morphology of surface scratches on diamond fly-cut KDP crystal is characterized and their effect on the laser damage resistance is theoretically and experimentally investigated. The results indicate that surface scratches could lower laser-induced damage threshold (LIDT) by modulating incident lasers and producing resultant local light intensifications. The induced maximum light intensity enhancement factors (LIEFs) are dependent on scratch shapes and dimensions. The diffraction effects originating from scratch edges are responsible for the strongest light intensification. Even for ultra-precision finished KDP surface with scratches that well satisfy the currently applied scratch/dig specification, the induced LIEFs are quite high, indicating that the actual defect dimension allowance should be amended and specified according to the defect-induced LIEFs. The effect of scratches on laser damage resistance is experimentally verified by the tested LIDT, which is approximately consistent with the simulation one. The morphologies of laser damage sites further confirm the role of scratches in lowering LIDT. This work could offer new perspective and guidance for fully evaluating the performance of ultra-precision manufactured optical materials applied in high-power laser facilities.