Surface damage features of sapphire by 1064nm Nd: YAG pulsed laser irradiation

Abstract

The problem of laser induced damage of optical materials is one bottleneck to restrict laser power levels and beam quality enhances unceasingly. The research on laser induced optical material damage, improving optical material laser damage threshold, becomes a hot issue in the development of laser technology. In this paper, laser-induced sapphire damage morphology using nanosecond 1064nm Nd: YAG is reported. Analyzed the temperature variation of sapphire inclusion under different laser fluence irradiation, and the temperature variation of inclusion's dimension radius by finite element method. The laser-induced damage experiment of sapphire materials are investigated (pulse width is 6ns). At the same time, the sapphire laser-induced damage threshold, the damage position distribution, the influence of different laser fluence on the damage area and damage growth characteristics are analyzed. Results show that the inclusion absorption mechanisms can better explain the sapphire under the nanosecond laser pulse irradiation damage, and simulation results are in agreement with the experimental results. In addition, for 1-on-l irradiation, the surface damage area for sapphire surface increase linearly, for s-on-1 irradiation, the damage area on the back surface increases exponentials with the increase of shot number.