Thermal analysis of micromirrors for high-energy applications

This paper presents the results of an investigation of the thermal mechanism between lasers and surface-micromachined micromirrors. Finite element models using ABAQUS are established and used to study the temperature distribution on the surface of micromirrors under high-power laser illumination. It is shown that heat conduction through the gas gap between the mirror surface and the substrate is the dominant thermal dissipation mechanism for high surrounding gas pressure, while heat conduction through the flexures is dominant for low surrounding gas pressure. Based on the simulation results, two novel methods are proposed in order to tolerate more power input under low surrounding gas pressure. The results of optical power testing validate these models, and indicate that these two approaches are efficient in improving micromirror performance for high-energy applications.