The effect of ion beam etching process on laser damage resistance of fused silica

The effect of ion beam etching process on the surface quality, the surface roughness and the laser-induced damage threshold at 351nm was carried out. Research results reveal that the laser-induced damage threshold of fused silica was enhanced with the increase of etching depth when the etching depth was less than 800nm, and could be further enhanced about 30% at 800nm etching depth, however the laser-induced damage threshold began to decrease with the further increase of etching depth(more than 800nm). The test results of surface microtopography, laser damage morphology, and surface roughness reveal that the ion beam etching process can remove polishing re-deposition layer without degrading the surface condition at a smaller etching depth so as to enhance the laser-induced damage threshold of fused silica, however further ion etching which can produce impurity particle often results in a decrease rather than an increase of laser-induced damage threshold.