Laser removal of micron contaminant colloidal refractory and poor laser absorption particles from super-smooth optical substrate

Micron and submicron SiO2 polishing particle and remaining polishing powder contaminations on super-smooth glass surface adversely influences: (i) the performance and quality of glass and (ii) the productivity of optical product. To remove these particles, multimode Nd:YAG pulse laser was used to vaporize an applied thin film of black paint on the substrate surface. Experiments to examine the removal efficiency of polishing particles from poor laser absorptive super-smooth K8 optical glass (K8 OG) substrate were performed, and they showed good workability of the cleaning method. Based on the experimental and theoretical results, some mechanisms related to the laser removal of the contaminating colloidal particles from the surface were described.