Aspherical High-Speed Varifocal Piezoelectric MEMS Mirror

A high-speed large-amplitude piezoelectric varifocal MEMS micromirror is reported. The mirror is capable of both quasistatic and resonant actuation. In quasi-static mode, the shape of the mirror can be tuned to aspherical shapes by adjusting the excitation of individual electrodes using a superposition principle. In resonant mode, the mirror was shown to achieve the total optical power of +/− 100 m
⁻¹
at 90kHz. A novel figure of merit for resonant varifocal mirrors is introduced as a product of mirror diameter, frequency and optical power, and state-of-the-art devices are reviewed and compared. Our device features the highest figure of merit ever reported.