Incident laser modulation of a repaired damage site with a rim in fused silica rear subsurface  

作　　者：李莉 向霞 祖小涛 袁晓东 贺少勃 蒋晓东 郑万国 

机构地区：[1]Institute of Physics and Electronics,University of Electronic Science and Technology of China,Chengdu 610054,China [2]Research Center of Laser Fusion,China Academy of Engineering Physics,Mianyang 621900,China

出　　处：《Chinese Physics B》2012年第4期351-356,共6页中国物理B（英文版）

基　　金：supported by the Fundamental Research Funds for the Central Universities (Grant No. ZYGX2010J045);the National Natural Science Fundation of China and the China Academy of Engineering Physics United Foundation (NSAF) (Grant No. 11076008);the Foundation for Young Scholars of University of Electronic Science and Technology of China (Grant No. L08010401JX0806)

摘　　要：Local CO2 laser treatment has proved to be an effective method to prevent the 351-nm laser-induced damage sites in a fused silica surface from exponentially growing, which is responsible for limiting the lifetime of optics in high fluence laser systems. However, the CO2 laser induced ablation crater is often surrounded by a raised rim at the edge, which can also result in the intensification of transmitted ultraviolet light that may damage the downstream optics. In this work, the three-dimensional finite-difference time-domain method is developed to simulate the distribution of electrical field intensity in the vicinity of the CO2 laser mitigated damage site located in the exit subsurface of fused silica. The simulated results show that the repaired damage sites with raised rims cause more notable modulation to the incident laser than those without rims.Speeifically,we present a theoretical model of using dimpled patterning to control the rim structure around the edge of repaired damage sites to avoid damage to downstream optics. The calculated results accord well with previous experimental results and the underlying physical mechanism is analysed in detailLocal CO2 laser treatment has proved to be an effective method to prevent the 351-nm laser-induced damage sites in a fused silica surface from exponentially growing, which is responsible for limiting the lifetime of optics in high fluence laser systems. However, the CO2 laser induced ablation crater is often surrounded by a raised rim at the edge, which can also result in the intensification of transmitted ultraviolet light that may damage the downstream optics. In this work, the three-dimensional finite-difference time-domain method is developed to simulate the distribution of electrical field intensity in the vicinity of the CO2 laser mitigated damage site located in the exit subsurface of fused silica. The simulated results show that the repaired damage sites with raised rims cause more notable modulation to the incident laser than those without rims.Speeifically,we present a theoretical model of using dimpled patterning to control the rim structure around the edge of repaired damage sites to avoid damage to downstream optics. The calculated results accord well with previous experimental results and the underlying physical mechanism is analysed in detail

关 键 词：laser-induced damage fused silica mitigated damage site three-dimensional finite- difference time-domain 

分 类 号：TN24[电子电信—物理电子学]