Optical methods for characterization of MEMS device motion

Micro-electromechanical system (MEMS) devices are small compared to normal mechanical devices, but they are still large compared to the wavelength of visible light. Thus, simple low-cost optical measurement techniques can be adapted for precise characterization of the motions of these small objects. The results of such measurements are important for veriication of simulations, especially for devices in which nonlin-ear eeects such as squeeze lm damping play a signiicant role. The advantages and challenges of optical metrology for MEMS are examined using an electrostatically-actuated microgripper structure as an example device. Interferometric measurements of static rotation and of small-signal sinusoidal and impulse responses are presented.