PZT actuated micromirror for nano-tracking of laser beam for high-density optical data storage

A micromirror actuated by piezoelectric cantilevers is proposed as a fine-tracking device for high-density optical data storage. Metal/PZT/metal thin film actuators translate an integrated micromirror along the out-of-plane vertical direction. The parallel motion of the micromirror steers linearly the optical path of the reflected laser beam. Numerical analysis shows that the actuated micromirror can satisfy the tracking speed imposed by the requirement on the access time for the high-density optical data storage up to few tens Gbit/in2. In this paper, preliminary characteristics of the micromachined PZT actuated micromirror (PAM) are reported. The design and the fabrication process of the PZT actuated micromirror are described. Only a 3600 angstroms-thick PZT film deposited by sol-gel process shows both good electrical and mechanical characteristics for the actuators. The micromirror can be easily actuated up to several micrometers under low voltage operation condition.