Optoelectronic System for Studying Nanodisplacements of Moving MEMS Elements

An experimental structure of an optoelectronic system for contactless measurements of micro- and nanodisplacements of moving MEMS elements is considered. The system is based on a heterodyne interferometer with a frequency-stabilized He–Ne laser and an acousto-optical modulator of laser radiation. A resolution of less than 1 nm in terms of the moving element displacement is reached in experiments by applying voltage pulses with amplitudes up to 1 V on the MEMS structure; moreover, the displacement amplitude is found to be a linear function of the control voltage with sensitivity of 100–200 nm/V. No hysteresis is observed on the curve plotted in the coordinates of the element location and control voltage.