Damage performance of thin-film beam splitter for third harmonic separation under simultaneous exposure to 1 ω and 3 ω pulses

Abstract

Laser damage behaviors of thin-film beam splitters for third harmonic separation were investigated under the simultaneous exposure of fundamental frequency (1 ω) and the third harmonics laser beam (3 ω). The samples were prepared by conventional e-beam evaporation, and the surface laser-induced damage thresholds (LIDT) of the samples were obtained for the irradiations of 3 ω only and 3 ω with various fluence of 1 ω. It was found that external 1 ω can raise damage probability of multilayer films; the higher the 1 ω energy density, the lower the damage threshold. Additionally, numerical simulation of damage probability was given for the simultaneous exposure to two beams.