Research on Laser-Induced Damage Post-Restoration Morphology of Fused Silica and Optimization of Patterned CO₂ Laser Repair Strategy

Fused silica has become the preferred optical material in the field of inertial confinement fusion (ICF) due to its excellent performance; however, these costly optical elements are vulnerable, and their manufacture is time-consuming. Therefore, the restoration of laser-induced damage for these optical elements is of great value. To restrain the post-restoration raised rim problem in the CO2 laser repair process to improve the restoration quality, the separate influences of key parameters of laser power, irradiation duration, and laser beam diameter on post-restoration pit morphology are compared in combined simulation and experimental studies. An optimized, patterned CO2 laser strategy is proposed and verified; the results indicate that, with the strategy, the rim height decreases from 2.6 mu m to 1.52 mu m, and maximal photo thermal absorption is decreased from 784.2 PPM to 209.43 PPM.