Study on thermal effect and thermal stress effect of multilayer thin films induced by pulsed laser

Abstract

In order to improve the laser-induced damage threshold (LIDT) of thin film optical elements in laser systems, the thermal damage and thermal stress damage processes in thin films induced by laser are analyzed. Based on the theoretical knowledge of heat conduction, material mechanics and thermoelasticity, the mathematical model of multilayer optical thin films irradiated by single-pulse Gauss laser is established. The active heat conduction equations and thermoelastic equilibrium differential equations under the model are established. The analytical solutions of temperature and thermal stress in multilayer optical thin films induced by laser are derived and calculated. Through software calculation and simulation, the distributions of temperature field and thermal stress field are obtained. By discussing and analyzing the simulation results, the influencing factors and distribution rules of temperature rise and thermal stress are obtained, which provide theoretical basis for preparing thin films with high laser-induced damage threshold.