Research Projects

Resistive-switching of phase-change cells in Fabry-Perot resonator structures has led to the development of high-resolution, fast, and non-volatile optoelectronic color displays and holograms. Phase-change meta-devices, a form of switchable dielectric, can provide novel functionalities such as beam steering, perfect infrared absorbers and modulators, and planar and re-configurable thin-film lenses. The proposed work of optically or electrically induced structural changes in the electrical or optical properties of phase-change devices is appealing in several respects. Conventional phase-change devices, such as memories, are typically two-terminal devices. However, the introduction of a third terminal (or gate) could provide new possibilities, such as ultra-fast optically-triggered phase-change switches, 3-terminal phase-change logic, and even a form of chalcogenide-based field-effect transistor. 3-terminal phase-change devices have already been explored in the area of RF-switching, where the 3rd terminal is used as an electrical heater to thermally switch a phase-change cell between high and low resistance states. This proposed project aims to develop optically triggered switches that could potentially deliver much faster switching times, as ultra-fast laser pulses can bring the switching time for phase-change materials down to the picosecond regime. The ability to access both excitation and detection modes simultaneously should help clarify unresolved aspects of the switching process in phase-change devices, such as the role of heat and the electric field on the threshold-switching mechanism.