Photoluminescence defects on subsurface layer of fused silica and its effects on laser damage performance

Abstract

Subsurface defects of polished fused silica optics are responsible for igniting laser damage in high power laser system. A non destructive measurement technique is developed to detect subsurface photoluminescence defects of fused silica. The fused silica samples polished by different vendors are applied to characterization of subsurface defects and measurement of damage performance. Subsurface photoluminescence defects of fused silica are evaluated by confocal fluorescence microscopy system. Laser induced damage threshold and damage density are measured by 355 nm nanosecond pulse laser. The results show a great differential subsurface quality of fused silica samples. Laser induced damage performance has a good correlation with subsurface defects. This paper shows a new non destructive measurement technique to detect photoluminescence defects on the subsurface layer of polished fused silica. It is very valuable to increasing laser damage performance and improving production-manufacturing engineering of optics.