Improve the laser damage resistance of fused silica by wet surface cleaning and optimized HF etch process

摘要

Fabrication-induced metal contaminations and subsurface damage are generally identified as the laser damage initiators that are responsible for the laser induced damage in fused silica. In this paper, the removal of those two initiators are realized by two methods: wet chemical surface cleaning and optimized HF-based etch process. Two kinds of chemical leaching are used to removing the Ce and other metal impurities respectively. In order prevent the redeposition of the reactive byproducts during HF etch process, we optimized the traditional HF etch process in two ways: absence of NH_4F in etch solution and presence of megasonic & ultrasonic agitation during & after etch respectively. And laser damage tests show that these two treatments greatly improve the laser damage resistance of fused silica.