短脉冲激光辐照下熔融石英薄膜的损伤机理  

Damage Mechanism of Fused Silica Optical Dielectric Film Irradiated by Short Pulse Laser

作　　者：黄才华[1] 薛亦渝[1] 夏志林[1] 赵元安[2] 杨芳芳[1] 郭培涛[1] 

机构地区：[1]武汉理工大学汽车工程学院,湖北武汉430070 [2]中国科学院上海光学精密机械研究所,上海201800

出　　处：《武汉理工大学学报（信息与管理工程版）》2008年第6期905-908,共4页Journal of Wuhan University of Technology：Information & Management Engineering

基　　金：国家自然科学基金资助项目(60708004);国家自然科学基金资助项目(10804090)

摘　　要：激光诱导薄膜损伤过程中,雪崩离化(AI)和多光子离化(MPI)的性质和作用到目前仍然存在争议。基于STUART等人的电子密度演化方程,运用数值模拟方法,研究了脉宽为τ∈[0.01,5]ps范围内单脉冲激光作用下熔融石英薄膜中电子密度演化过程;讨论了初始电子密度、激光脉冲宽度对阈值功率密度和阈值能量的影响;分析了初始电子密度、激光脉冲宽度对多光子离化及雪崩离化的影响。研究结果表明,在所研究的脉宽范围内,对于熔融石英光学薄膜、飞秒激光诱导损伤以雪崩离化为主导,多光子离化的影响随着脉宽的降低而增强,雪崩离化所需种子电子主要来源于多光子离化。There exists some controversial between the nature of the avalanche ionization （AI） and the role of the multi - photon ionization （MPI）. Based on Stuart et al. ＇s electron density evolution equation ,the electron density evolution process in fused sili- ca film irradiated by short - pulse laser for τ∈[0.01,5]ps were studied by means of numerical method. The effects of initial electron density Ni and laser pulse width T on laser threshold intensity lth and damage threshold fluence. Fth were analyzed respectively. The effects of Ni and τ on MPI and AI were also discussed. The results show that, for fused silica film, the laser - induced damage is dominated by AI, the effect of MPI increases with the decrease of pulse width τ. The seed electron generation needed in AL comes chiefly from MPI.

关 键 词：激光诱导损伤 多光子离化 雪崩离化 初始电子密度 损伤阈值能量 

分 类 号：TN249[电子电信—物理电子学] O242.1[理学—计算数学]