Wavefront Sensor in Measurements of MEMS Vibrations

The paper discusses an application of Shack-Hartmann wavefront sensor with stroboscopic illumination for measurements of the vibration modes at resonance frequencies of a MEMS devices. The wavefront sensor estimates the local slopes of the wavefront by measuring the displacement of light spots created by microlens array on the camera plane. The goal of the work is to investigate the features of the proposed method. Amplitudes of vibration modes of a MEMS square membrane are measured and compared with data obtained from the stroboscopic interferometry realized in Twyman-Green configuration. The difference in PV values of the vibration amplitude is less than 52 nm (λ/12). It confirms the high accuracy of the measurement. Moreover, in this case the Shack-Hartmann wavefront sensor enables to simplify the system configuration and reducing the impact of the environmental conditions on the measurement result.