A micromachined thermo-optical light modulator based on the VO 2 phase transition

Abstract

Vanadium dioxide (VO 2 ) thin film undergoes a semiconductor-to-metal phase transition at about 68 o C, which is accompanied with abrupt changes in its optical properties. A light modulator array has been developed by surface micromachining based on this thermally induced optical switching. The good thermal isolation and the small thermal mass of the micromachined pixels prevent thermal cross talk and provide advantages of low power consumption as well as high switching speed. The VO 2 pixel design was optimized by thermal and optical simulations. Active VO 2 thin film was fabricated by evaporation of vanadium film followed by thermal oxidation. The light modulator array has been realized in 64 × 64 format by surface micromachining using polyimide sacrificial layer. Preliminary characterization and testing result will be presented.