Stroboscopic Video Microscopy for In-Plane Motion Measurements Up to 2 MHz with Picometer Resolution

We present a setup for measuring in-plane motion of MEMS with picometer resolution. The system uses stroboscopic video microscopy to capture image sequences from periodic motions that are analyzed with gradient-based sub-pixel algorithms.The performance of the setup was demonstrated by measuring the frequency response along the length of an atomic-force cantilever and a dense mapping of the strain field on the surface of a flexoelectric MEMS device.Results demonstrate the superiority of our system compared to previous systems: 50 pm noise floor in single-shot experiments and frequency range up to 2 MHz.