Investigation on beam-size effect on sub-picosecond LIDT of dielectric oxide coatings

Abstract

Laser-induced damage experiments on HfO2 and Nb2O5 were performed with 500 fs pulse duration at 1030 nm wavelength. Threshold fluences in dependence of beam size have been determined within the range of effective beam diameters from 40 µm up to 220 µm. The results suggest no dependence of beam size effect on effective beam diameters at least between 80 µm to 160 µm. The LIDT results indicate importance of appropriate focusing conditions and beam measurement to qualify the optics for use in lasers with large beam sizes.