Li Yuan, Yan Hongwei, Yang Ke, Yao Caizhen, Wang Zhiqiang, Zou Xinshu, Yan Chunyan, Yuan Xiaodong, Ju Xin, Yang Liming
Department of Physics, University of Science and Technology Beijing, Beijing, 100083, China.
Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, 621900, China.
Sci Rep. 2017 Dec 19;7(1):17870. doi: 10.1038/s41598-017-18249-2.
Laser induced damage of fused silica is a serious problem for high power laser systems, and damage precursors are mainly induced by manufacturing processes. In this work, fused silica samples were prepared from a manufacturing process including grinding, polishing and etching procedures. The chemical disorder of the prepared samples was inspected by using fluorescence microscopy and ultra-violet fluorescence spectrometer. The physical disorder was characterized by using Infrared and Raman spectrometer. Laser induced damage thresholds (LIDTs) were measured in R-on-1 mode by 355 nm 6.4 ns laser pulse. Results showed that with the manufacturing processes transforming from grinding to etching, the magnitude of fluorescence point defects reduced while their types did not change, the Si-O-Si bonds of prepared samples were strained and the strained bonds were mitigated. The LIDTs increased with the reducing of fluorescence defects and strained Si-O-Si bonds. However, these structural defects can not be eliminated by the current manufacturing process. Improvements may be needed to eliminate the structural defects for a higher LIDT of fused silica.
激光诱导的熔融石英损伤是高功率激光系统面临的一个严重问题，损伤前驱体主要由制造工艺引起。在本工作中，通过包括研磨、抛光和蚀刻工序的制造工艺制备了熔融石英样品。使用荧光显微镜和紫外荧光光谱仪检查所制备样品的化学无序性。使用红外光谱仪和拉曼光谱仪对物理无序性进行表征。通过355 nm、6.4 ns激光脉冲以1对1模式测量激光诱导损伤阈值（LIDT）。结果表明，随着制造工艺从研磨转变为蚀刻，荧光点缺陷的数量减少而其类型不变，所制备样品的Si-O-Si键发生应变且应变键得到缓解。LIDT随着荧光缺陷和应变Si-O-Si键的减少而增加。然而，当前的制造工艺无法消除这些结构缺陷。可能需要改进以消除结构缺陷，从而提高熔融石英的LIDT。
