光子学报, 2009, 38 (6): 1375, 网络出版: 2010-05-10
波段外脉冲激光对锗透镜热冲击效应的数值与实验研究
Numerical and Experimental Study of Thermal Shock Effect on Germanium Lens Induced by Out-of-band Pulsed-laser
摘要
基于热传导及热弹性力学的基本关系式,建立了激光辐照锗透镜的热力耦合数学物理模型,对瞬态热传导方程和应力平衡方程进行有限元数值求解,得到了锗透镜的温度场和应力场分布,并利用波长1.06 μm,脉冲宽度10 ns的Nd∶YAG脉冲激光对锗透镜进行了热冲击实验研究.数值分析表明,热应力损伤在锗透镜的脉冲强激光损伤中占据主导地位,在短脉冲激光辐照下,锗透镜出现热应力损伤的激光能量密度小于出现熔融损伤的激光能量密度,热应力损伤主要集中在光斑中心区域并体现为压应力损伤,将使材料表面出现裂纹或剥落,实验结果与数值分析基本相符.
Abstract
The thermal-mechanical physical model of Ge lens irradiated by pulsed-laser was set up based on heat conduction and thermal elastic mechanics theories.The heat conduction differential equation and stress-balance equation were solved by the finite elements method and the transient temperature field and thermal stress field were obtained.Experiment about the thermal shock effect of Ge lens irradiated by Nd∶YAG laser(1.06 μm,10 ns)was carried out.The numerical simulation shows that the thermal stress damage dominants in the damage mechanism,thermal stress induced crack lines and flaking off will appear on the lens at low energy density levels,and with more laser energy the melting zone of Ge will be reached.The experiment results match the numerical simulation basically.
牛燕雄, 姜楠, 张书练, 张雏, 黄峰, 张鹏, 杨海林, 陈燕. 波段外脉冲激光对锗透镜热冲击效应的数值与实验研究[J]. 光子学报, 2009, 38(6): 1375. NIU Yan-xiong, JIANG Nan, ZHANG Shu-lian, ZHANG Chu, HUANG Feng, ZHANG Peng, YANG Hai-lin, CHEN Yan. Numerical and Experimental Study of Thermal Shock Effect on Germanium Lens Induced by Out-of-band Pulsed-laser[J]. ACTA PHOTONICA SINICA, 2009, 38(6): 1375.