Mechanism of third-harmonic laser-induced damage on fused silica surface with processing-introduced metal absorbers

A laser-induced damage model has been built for fused silica surface with metal particles as absorbers, which are introduced by processing. The evolution of the temperature field around absorbers during laser irradiation was simulated, and shows that the temperature at the hottest point will soon reach the critical temperature of damage in a pulse time. Damage densities of samples with and without etching have been experimentally compared, revealing the strong correlation between metal particles amount and damage density. Moreover, both simulation and experiment show that, the metal particles in fused silica surface are important damage precursors, which decrease the material’s laser damage threshold.