实验研究了不同激光预处理参数对于纳秒激光多脉冲作用下HfO2/SiO2反射膜损伤形态转化的影响。通过对比两类损伤扩张性和对薄膜功能性破坏机制, 提出激光预处理技术的重要意义在于抑制损伤形态转化过程。通过薄膜损伤形态分析揭示了激光预处理作用机制为节瘤缺陷的去除和亚表面吸收前驱体的形成两方面的综合作用。实验结果表明: 预处理后薄膜损伤形态转化特征曲线向更高通量和更多发次方向平移。针对现有工艺下的薄膜, 采用高通量、两台阶的预处理参数组合能够获得兼顾效率的最佳收益, 其零几率损伤形态转化阈值最高可以提升140%。

The effects of varied laser conditioning parameters on the damage morphology change process of HfO2/SiO2 reflective film under nanosecond pulse were experimentally studied in this paper. By comparing of damage expansion and the influence on spectra for two types of damage, the role of laser conditioning is illuminated to restrain the process of damage morphology change process. The two contrary impacts of laser conditioning on thin film, nodule clean up and absorbing precursor formation, were revealed by damage morphology analysis. The experiment result shows that the contours of damage morphology change thresholds will shift to higher laser fluence and more shots after laser conditioning. In addition, considering efficiency and profit of laser conditioning, the combination of higher laser fluence and two scanning steps could have the best choice in morphology changing elimination, and the morphology change threshold could increase to 140% in the best case.