Abstract: Vanadium dioxide (VO.sub.2) based infrared spatial light modulators (SLM) in four embodiments are disclosed:(1) A VO.sub.2 thin film is deposited on a planar diode array. Each diode constitutes a "pixel" of the SLM. Power provided to a diode permits accurate thermal control about the thin film's hysteresis. Initial biasing of the diode array is required to the base of the VO.sub.2 's hysteresis curve.(2) & (3) VO.sub.2 is deposited on a thermoelectric array which can be an array of doped lines of p and n type material or a conductive material between two electrical contacts. The pixels have the ability to both heat and cool the VO.sub.2 film, thereby allowing the array to be operated in a bistable mode. Bistable operation requires external biasing to the center of the VO.sub.2 's hysteresis curve.(4) A VO.sub.2 thin film deposited on a substrate which is spaced a distance, L, from an array of vertical-cavity surface-emitting lasers for heating the VO.sub.2.

Abstract: A method of preparing an active surface layer on a semi-insulating GaAs substrate comprising the steps of ion implanting a surface layer with silicon to form an n-type active layer and ion implanting a buried diffusion layer beneath the active layer with boron to prevent defects in the substrate from influencing the active region. The method is particularly useful for GaAs MESFETs.