Two-dimensional measurement of resonance in MEMS resonators using stroboscopic differential interference contrast microscopy

We report the two-dimensional (2D) measurement of resonance in MEMS resonators using stroboscopic differential interference contrast (DIC) microscopy, for the investigation of the linear and nonlinear oscillations of MEMS resonators. The DIC microscopy measures the interference of two sheared illumination light beams reflected from the sample surface to determine the differential surface deflection. By modulating the illumination light at the resonance frequency, the DIC image of the MEMS resonator periodically change its brightness and contrast with the sweeping illumination phase, which have been used to derive the oscillation amplitude and the resonance mode shape of the MEMS resonator. Comparing with conventional interference microscopy, the DIC microscopy can observe the surface deflection larger than the wavelength of the illumination light, enabling the measurement of nonlinear oscillations with a large oscillation amplitude. We demonstrate that the stroboscopic DIC microscopy can measure the 2D mechanical resonance with a high vertical resolution at the nanometer(nm)-scale, and a large measurement range of similar to 1 mu m, which is very promising for the investigation of linear and nonlinear oscillations of MEMS resonators. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

In this study, we report the two-dimensional measurement of resonance in MEMS resonators using stroboscopic differential interference contrast (DIC) microscopy. The DIC microscopy enables the observation of large-amplitude nonlinear oscillations and provides high vertical resolution and a large measurement range. This research is significant for the investigation of linear and nonlinear oscillations of MEMS resonators.