Characterization of GaAs-based micro-origami mirrors by optical actuation

We have performed optical actuation to characterize GaAs-based micro-mirrors fabricated by the micro-origami technique. Micro-origami makes use of the energy stored as strain between lattice-mismatched semiconductor epitaxial layers to create self-positioning, three-dimensional structures with simple and robust hinges. Mirrors studied in this work were GaAs plates grown on In0.22Ga0.78As/GaAs strained layers. Optical actuation was achieved by uniformly shining the 488-nm line of a high-power Ar+ laser on the mirrors. The laser light was either continuous wave (CW) or chopped with an acousto-optical modulator. Under a CW illumination of about 450 mW/mm(2), an angular deflection of the mirror of 0.5degrees was obtained. When actuated with modulated light, the first resonant mode of the mirror was experimentally detected at 25 kHz. Finite element analysis showed that the experimental results correspond to a longitudinal-bending resonant mode of the mirror. (C) 2004 Elsevier B.V. All rights reserved.