OPTIMIZED DESIGN, FABRICATION AND CHARACTERIZATION OF PZT UNIMORPH MICROACTUATORS FOR DEFORMABLE MIRRORS

ABSTRACT This paper describes an optimization of PZT unimorph membrane microactuators in view of their application to deformable mirrors (DMs). PZT unimorph actuators of various electrode designs, silicon membrane thickness, and membrane sizes were fabricated and characterized. A mathematical model was developed to further assist the optimization of membrane thickness and electrode sizes, and excellent agreement with experiment was obtained. For a 2.5rnm diameter actuator with 2#m thick PZT and 15#m thick silicon membrane, the measured vertical stroke was 5.4#m at 50V. The measured resonant frequency of the unimorph actuator was 47kHz, far exceeding the bandwidth requirement of most DMs (-lkHz)