Laser damage in fused silica, particularly ultraviolet laser damage, is still a key problem limiting the development of high-power laser systems. The traditional processing method of fused silica goes through the processes of grinding and chemical mechanical polishing (CMP). This method is time-consuming to achieve an ultra-smooth surface, and is easy to cause surface and sub-surface defects, resulting in a significant reduction in the surface damage threshold of the fused silica.
source https://phys.org/news/2020-11-fused-silica-high-threshold-chemical.html