长脉冲激光辐照下单层 HfO2薄膜的温度场分析

摘要

Optical coatings in a laser system are easily damaged ,so it is important to investigate the temperature field of the film irradiated by a long-pulse laser .A spatial axisymmetric finite element model of single layer HfO2 film with a high-absorptance platinum inclusion was used to study the thermal damage induced by a long-pulse laser .Influences on the temperatures of the film and substrate by the absorption coefficient and the depth of the platinum inclusion in the film were analyzed .The results show that the maximum temperature in film surface ,compared with pure HfO2 film ,can be increased more than one time when the depth of inclusion is 100nm ;w hen the depth of inclusion reaches 750 nm ,the temperature of substrate is higher than that of film ,w hich may cause first damage of the substrate .Results of the research can provide a reference for optical film design in the preparation and preprocessing of thin film ap-plied in the long-pulse system .%激光系统中的光学薄膜极易受到高能激光的辐照而产生热损伤，因此研究长脉冲激光作用下光学薄膜的温度场非常重要。建立了二维轴对称杂质模型，使用有限元方法计算了单层HfO2薄膜材料的瞬态温度分布，进一步分析了铂金杂质粒子的吸收系数、填满深度对膜层及其基底最大温升的影响。结果表明：相比于纯净HfO2薄膜，当薄膜中杂质粒子深度为100 nm时，其表面最大温度增加1倍左右；当粒子深度大于750 nm时，基底温度高于薄膜表面温度，从而可以使热损伤从薄膜基底开始。研究结果对于长脉冲激光系统中的光学薄膜的制备和预处理，具有一定的指导意义。