超声清洗与激光预处理对减反膜阈值的影响

Effects of ultrasonics cleaning and laser conditioning on the laser induced damage threshold of the antireflection

研究了超声清洗和激光预处理两种后处理手段对减反膜的损伤特性的影响。采用电子束蒸发技术制备了1 064 nm减反膜,利用超声清洗及激光预处理的方法分别对样品进行处理,并对处理前后的样品分别进行激光损伤阈值测试及破斑深度测量。结果表明:处理后减反膜的损伤阈值均有所提升,但激光预处理的阈值增强效果更加明显;超声清洗前后的破斑深度没有大的变化,而激光预处理后的破斑深度比处理前浅得多;原因在于超声清洗只能去除表面杂质,激光预处理可减少和抑制膜层内较深处的缺陷。

Effects of ultrasonic cleaning and laser conditioning of antireflective coatings on laser damage behaviors were investigated. The antireflective coatings at 1 064 nm were prepared by electron beam evaporation, and the samples were post-treated by ultrasonic cleaning and laser conditioning respectively. Laser induced damage threshold（LIDT） was measured and the damage morphologies were plotted by optical profiler. It was found that both ultrasonic cleaning and laser conditioning could improve the LIDT of coatings, but laser conditioning gained much higher enhancement. The damage depth had no obvious change before and after ultrasonic cleaning, while the depth became very shallow after laser conditioning compared with that before laser conditioning. The reason is that the ultrasonic cleaning only clears up the surface impurity of coatings, while laser conditioning can minimize or restrain the inner defects of coatings.