摘要光学元件的激光致损伤限制了激光系统向高功率大能量发展。为了研究光学元件材 料中分布的缺陷对于元件损伤特性的影响，本文分别数值比较了单缺陷模型和多缺陷模 型。结果表明，相同激光参数下多缺陷模型中缺陷的聚类效应使得其最大温升高于单缺 陷模型；此外，多缺陷模型由于考虑了缺陷分布的随机性，能够很好地反映实验中激光 损伤所表现出的概率特性。随后，在多缺陷模型的基础上研究了缺陷密度、缺陷尺寸、 激光脉宽等参数对损伤概率曲线和损伤阈值的影响，发现在其它参数一定的情况下，缺 陷密度增大、缺陷尺寸增大、激光脉宽减小，都会使损伤阈值明显减小，更易造成激光 致材料损伤。79439

毕业论文关键词 激光损伤 多缺陷模型 脉宽 缺陷密度 缺陷尺寸

毕 业 设 计 说 明 书 外 文 摘 要

Title Numerical study of laser-induced damage of optical materials based on multi-defect model

Abstract Laser-induced damage of optical elements limits the development of laser systems with high power and high energy。 In order to study the influence of defects on laser damage, this paper makes a comparison between single defect model and multi-defect model by numerical simulation。 Results show that under the condition of the same parameters, the effect of random clustering in multi-defect model makes its highest temperature rise higher than in single defect model。 Considering the random distribution of defects, multi-defect model can reflect the probability characteristics of laser damage。 Besides, influences of the parameters like defect density, defect size and pulse width on damage probability curves and damage threshold are studied based on multi-defect model。 It is found that under the condition of the same parameters, higher defect density, larger defect size and shorter pulse width can reduce the damage threshold obviously, and make the formation of laser-induced damage much easier。

Keywords Laser-induced damage Multi-defect model Pulse width Defect density Defect size

本科毕业设计说明书 第 I 页

目 次

1 引言 1

1。1 发展趋势以及瓶颈 1

1。2 激光诱导损伤机制 1

1。3 本文研究内容 3

2 缺陷模型 4

2。1 单缺陷模型 4

2。2 多缺陷模型 6

3 模型计算结果与分析 12

3。1 单缺陷温升模拟 12

3。2 双缺陷温升模拟 14

3。3 多缺陷温升模拟 15

3。4 脉宽对损伤概率曲线的影响