Study on the impact of grating absorption on substrate temperature under intense laser irradiation

Abstract

Grating absorption is a phenomenon influenced by various factors such as material properties, grating structure, and characteristics of the incident light. Under intense laser irradiation, the absorbed energy of the laser is converted into thermal energy, resulting in an elevated temperature of both the grating and substrate. This temperature rise significantly compromises the optical performance of the grating, thereby imposing constraints on the advancement of high-power laser systems. The numerical simulations were performed using the finite element method to investigate the effects of different absorptivity of grating, spot sizes, substrate materials (Fused silica, BK7 and Sapphire), and convective coefficients of air on the temperature distribution at various locations on the substrate under high-power laser irradiation (30kW/cm2). Comparative analysis reveals that selecting sapphire as the substrate material under high-power laser irradiation results in better heat dissipation.