Programming and Projection of Near IR Images Using ${\rm VO}_{2}$ Films

This letter reports the use of programmed optical states in a vanadium dioxide (VO₂) thin film for the projection of near infrared (NIR) images. The optical states are programmed by photothermal actuation from scanning a focused red laser on localized regions of the VO₂ thin film. The abrupt change in transmissivity of NIR wavelengths across VO₂´s solid-to-solid phase change is used to reflect a diffused NIR beam in the regions scanned by the red laser. The transmitted NIR beam is projected on a laser beam profiler. The results of a single scan from the red laser show images with a high contrast between the two phases of the material.