Laser Doppler Method for Mode Identification on Micro-Oscillators

摘要

The mechanical motion of a new class of micro-mechanical devices, known as micro electro-mechanical systems (MEMS) oscillators, is examined using the laser Doppler technique. Currently, experimental methods based on capacitance, induction, and Fabry-Perot interferometry are used to find resonance frequencies and to establish quality factors or Q's. The technique described in this paper is capable of distinguishing mode shapes, yielding calibrated displacements, and revealing the existence of flexural modes, in addition to finding resonance frequencies and establishing Q's as the other techniques do. Because full-field laser vibrometry measurements provide an understanding of the modal composition of the systems, it can be used to refine the design and construction of these devices.