为了提高熔石英基片对351 nm短波长激光的损伤阈值,采用光栅式扫描方式,利用CO2激光器输出10.6 μm波长的激光,对氢氟酸蚀刻后的小口径熔石英基片表面进行功率周期递增的辐照扫描。结果表明,经过CO2激光预处理后的熔石英基片,表面微观形貌得到了有效改善; 利用S:1的方法测量熔石英基片损伤阈值。结果发现,在中度激光抛光的程度下,其零概率损伤阈值提高了30%左右,且对透射波前没有造成不利影响,从而证明了CO2激光预处理提高熔石英基片抗激光损伤能力的有效性。

In order to improve the damage threshold of fused silica chip, the bare fused silica chip with small aperture etched by hydrofluoic acid is scanned by 10.6 μm CO2 laser with a raster scaning form, and the laser power increases periodically. Results show the surface micro-topography of the pretreated chip is greatly improved. The means of S:1 method is used to measure its damage threshold. Under the conditions of moderate laser polishing, the zero probability damage threshold of the fused silica chip is increased by 30%, and no negative effect on transmission wavefront is introduced. The validity of CO2 laser pretreatment enhancing the bare fused silica chip damage resistant is proved.