薄膜内杂质吸收热损伤机制的有限元分析

FEA of thermal damage mechanism due to absorption of impurities in thin films

在介质薄膜中,薄膜中的嵌入杂质或缺陷是导致薄膜激光损伤的关键因素。为了理解球状杂质对薄膜热力学损伤的影响,以热传导方程为依据,采用有限元方法模拟了厚度为500nm的介质薄膜在激光辐射下的球状杂质吸收对薄膜的温度场分布的影响。分析了不同大小和深度的球状杂质对薄膜温度场的影响,发现大而浅的杂质对薄膜的温度场的影响较大,且薄膜在激光单脉冲作用时间内,最高温升不会出现在激光功率密度达到峰值的时刻,而是稍微滞后。

The impurity defect of a dielectric single-layer optical thin film is crucial to the film＇s laser damage. To understand thermodynamically the influence of spheroidal impurities on the laser damage of optical thin film, FEM was used to simulate how the thermal absorption of spheroidal impurities affects the temperature field distribution in a 500nm-thick dielectric thin film under laser irradiation, based on the heat transfer equations. Analyzing the effects of different sizes and depths of spheroidal impurities on the temperature field of the film, it was found that the big and shallow impurities affect greater the temperature field and that the maximum temperature rise is impossible at the moment the power density of laser comes up to its peak value but slowed slightly when the film is irradiated by single pulse laser.