Zhong Yaoyu, Dai Yifan, Shi Feng, Song Ci, Tian Ye, Lin Zhifan, Zhang Wanli, Shen Yongxiang
Laboratory of Science and Technology on Integrated Logistics Support, College of Intelligence Science and Technology, National University of Defense Technology, 109 Deya Road, Changsha 410073, Hunan, China.
Materials (Basel). 2020 Mar 13;13(6):1294. doi: 10.3390/ma13061294.
Nanoscale laser damage precursors generated from fabrication have emerged as a new bottleneck that limits the laser damage resistance improvement of fused silica optics. In this paper, ion beam etching (IBE) technology is performed to investigate the evolutions of some nanoscale damage precursors (such as contamination and chemical structural defects) in different ion beam etched depths. Surface material structure analyses and laser damage resistance measurements are conducted. The results reveal that IBE has an evident cleaning effect on surfaces. Impurity contamination beneath the polishing redeposition layer can be mitigated through IBE. Chemical structural defects can be significantly reduced, and surface densification is weakened after IBE without damaging the precision of the fused silica surface. The photothermal absorption on the fused silica surface can be decreased by 41.2%, and the laser-induced damage threshold can be raised by 15.2% after IBE at 250 nm. This work serves as an important reference for characterizing nanoscale damage precursors and using IBE technology to increase the laser damage resistance of fused silica optics.
由制造过程产生的纳米级激光损伤前驱体已成为限制熔融石英光学元件抗激光损伤性能提升的新瓶颈。本文采用离子束蚀刻（IBE）技术，研究了不同离子束蚀刻深度下一些纳米级损伤前驱体（如污染物和化学结构缺陷）的演变情况。进行了表面材料结构分析和抗激光损伤性能测量。结果表明，IBE对表面具有明显的清洁作用。通过IBE可以减轻抛光再沉积层下方的杂质污染。化学结构缺陷可显著减少，IBE后表面致密化减弱，且不会损害熔融石英表面的精度。在250nm波长下，IBE处理后，熔融石英表面的光热吸收可降低41.2%，激光诱导损伤阈值可提高15.2%。这项工作为表征纳米级损伤前驱体以及利用IBE技术提高熔融石英光学元件的抗激光损伤性能提供了重要参考。
