Damage threshold improvement of fused silica chip by CO2 laser pretreatment

In order to improve the damage threshold of fused silica chip, the bare fused silica chip with small aperture etched by hydrofluoric acid is scanned by 10.6 μm CO2 laser with a raster scanning 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.