Responding to the needs of microelectromechanical systems (MEMS) manufacturers for an effective and dynamic measurement technique, Veeco Instruments Inc. of Tucson, Ariz., has developed the Wyko Dynamic MEMS measurement system to control the fabrication process and to ensure device quality. The system comprises an optical profiler -- a white light interferometer -- an additional strobed LED illumination source, drive/synchronization electronics and proprietary analysis software to enable visualization and measurement of a device in motion. Data images are combined to generate a high-resolution 3-D video. Vibrating structures blur or distort an optical image, yielding an inaccurate measurement of their range of motion. But if the motion is periodic and of primarily one frequency, the user can strobe the light source in synchronization with the motion to effectively freeze it. Optical profiling techniques can then characterize the device's shape, and a series of measurements at varying amplitude, phase and/or frequency can describe the full range of motion. The system quantifies critical dimensions and motion. Template-driven software tracks features across multiple data frames so that key device parameters such as lateral and vertical range of motion, shape/distortion, radius of curvature, resonant frequency and settling time can be determined. Applications include accelerometers, sensors, flexing cantilevers, rotating motors, gears, oscillating resonators and optical switches. The system accommodates any device with periodic motion, even at frequencies of up to 1 MHz, and it measures surface features from nanometer-scale roughness to millimeter-scale step heights.