Damping of a micro-resonator torsion mirror in rarefied gas ambient

Damping in resonating MEMS mirrors has a profound effect on the dynamical behavior. The validity of the existing theories is investigated in this work by theoretical and experimental means. The squeeze-film model with artificial viscosity and the molecular dynamics model are adapted for the case of a torsion mirror under a wide range of vacuum levels. The considered ambient pressure varies from atmospheric to a pressure under which structural damping prevails. High resolution experiments have been conducted on dedicated devices. Two independent experimental damping extraction methods have been employed for substantiating the validity of the measured parameters. Although the theoretical models agree favorably with the experimental data, it appears they provide slightly different predictions under different operating regimes.