Scratch healing with CO2 Laser on fused silica for surface repair

Abstract

To prevent the disposal of minimally damaged lenses that fall outside the acceptable scratch and dig tolerance levels, an experimental study was conducted to repair mechanical scratches on a fused silica surface. The scratches were created using a diamond tip and then repaired using a CO2 laser. Various loads on the diamond lip and laser output power were tested. The transmission changes and subsurface damages were analysed. The surface quality analysis was performed using a white light interferometer, while the subsurface damage analysis was performed using optical coherence tomography. Local absorption differences can be quantified using photothermal deflection. To significantly enhance local transmittance, brittle and ductile scratches of various depths have been successfully healed.