Effect of subsurface impurities of fused silica on laser induced damage probability

Based on Mie theory and heat equation, combined with the measurement of the main components for impurities on the subsurface of fused silica by ICP-OES, a model for calculating laser-induced damage probability on the surface of optical components by absorbing impurities was presented. Based on this theoretical model, the critical fluence required to initiate damage by various impurities as a function of particle radius and the damage probability on the surface of fused silica induced by the impurities with different distribution were investigated. The damage probability on the surface of fused silica was measured under the irradiation of 355 nm laser with different beam sizes. Comparison of the calculated and experimental results was conducted. The contribution to laser-induced damage probability for these three impurities was analyzed (Cu Al CeO2) with same particle distribution parameters. Through the model, the effect of various potential absorbing impurities embedded in the subsurface of optical substrates or films on damage probability can be analyzed.