为了研究高功率固体激光装置内污染诱导光学元件损伤问题,基于有限元数值方法,结合污染物诱导熔石英损伤机理,给出了熔石英样片在高功率脉冲激光辐照下的温度场和应力场分布.结果表明,激光脉冲辐照过程中主要以污染物的温度升高为主,最高至2800K,而样片温升不大,仅为7K;在激光脉冲辐照后100μs的时间内,样片表面中心快速升温至2200K,而边缘处仅为700K,在较短的距离内温度变化剧烈,由此产生的热应力导致表面发生损伤;损伤区域中心表现为压应力,边缘为拉应力,最大可达30.73MPa.测试了污染物诱导样片损伤斑的微观显微形貌,实验结果和理论计算结果符合较好.%In order to study the laser-induced damage mechanism in inertial confinement fusion system, temperature and thermal stress distributions in the fused silica, heated by repetition frequency laser, were given by means of finite element methods. The simulated results indicate the temperature of the contaminations rise to 2800K during the pulse laser irradiation, but the fused silica' s temperature mainly rise from 300K to 2200K in 100μs after irradiation, and damage induced by the thermal stress occurs. The strong compressive in the damage region is about 30. 73MPa. The highest stress outside the damage region is deviatoric hoop stress. The damage morphologies were tested by means of optical microscopy. The simulated outcomes correspond to the experiment result.
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