CO2 laser mitigation of the ultraviolet laser damage site on a fused silica surface

The CO2 laser mitigation method has been developed to mitigate the ultraviolet laser damage site on a fused silica surface. The mitigation process was monitored by an on-line white light scattering imaging system in order to ensure that the mitigation is successful. Additionally, a total internal reflection microscope was utilized to analyze the mitigation pit. By optimizing the laser mitigation parameters, the rough damage site can be replaced by a smooth Gaussian-shaped mitigation pit. The chemical composition of the damage sites and the CO2 laser mitigation pits was also measured with energy dispersive x-ray spectroscopy. It reveals that the oxygen deficiency center defect of the ultraviolet laser damage site is removed after CO2 laser mitigation, which helps us better understand the CO2 laser mitigation process. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)