Performance improvement and mechanisms of fused silica-based SiO2 coating by conditioning by CO2 laser

In this study, a continuous wave CO2 laser was used to process silicon dioxide (SiO2) anti-reflection (AR) films coated on a fused silica substrate by the sol-gel method. The effects of laser conditioning on the properties of AR coatings at 1064 nm were investigated to determine the relationship between laser power and coating properties. The structural and mechanical properties of the processed films were measured by FTIR, UV-Vis spectroscopy, and nanoindentation. After laser conditioning, it was found that the mechanical strength of the coating improved, the roughness of the coating reduced to 9.7 nm, and the laser-induced damage threshold (LIDT) of the coating at 1064 nm wavelength increased to 7 J/cm2.