Numerical analysis of thermal response of mid-infrared high reflectance coating under different laser irradiation angles

Abstract

Thermal response of mid-infrared high reflectance coating exposed to laser beam of wavelength of 4.3 μm at different incident angles was studied by numerical method. In this paper, the incident beam was modeled as a tapered wave with a Gaussian spectrum. Joule loss due to absorption in the absorptive layers was calculated analytically and temperature profile in the multilayer was presented. The temperature distributions of high reflectance coating with different incident angles of transverse electric (TE) mode and transverse magnetic (TM) mode laser beams were compared. For the TE mode laser, the highest temperature peak appears at the incident angle of 35°, for the TM mode, the magnitude of the temperature peak decreases with increasing incident angle.