Optical actuation of micromirrors fabricated by the micro-origami technique

TLDR

The micro‑origami technique enables simple, robust hinges for movable parts and is applicable to any pair of lattice‑mismatched epitaxial layers in semiconductors or metals. Micromirrors were fabricated by micro‑origami, using a multilayer AlGaAs/GaAs/InGaAs structure grown by MBE, with hinges and mirrors defined by photolithography, released by selective etching, and actuated optically by a 488 nm argon laser while their position was monitored via He–Ne laser reflection. Under continuous‑wave irradiation at 450 mW mm⁻², the mirrors deflected about 0.5°, and their frequency response exhibited a 25 kHz resonance.

Abstract

Micromirrors were fabricated by the micro-origami technique. This technique allows the fabrication of simple and robust hinges for movable parts, and it can be applied to any pair of lattice mismatched epitaxial layers, in semiconductors or metals. A multilayer structure, including AlGaAs/GaAs component layers and an InGaAs strained layer, was grown by molecular beam epitaxy on a GaAs substrate. After definition of the hinge and mirror’s shape by photolithography, the micromirrors were released from the substrate by selective etching. They moved to their final position powered by the strain release in the InGaAs layer. Optical actuation was achieved by irradiation with the 488 nm line of an argon laser, and the mirror’s position was measured by sensing the reflection of a He–Ne laser. Continuous wave irradiation with a power density of 450 mW/mm2 produced an angular deflection of the mirror of around 0.5°. The frequency response of the mirrors shows a resonance at 25 kHz.