Voltage switching of a VO₂ memory metasurface using ionic gel

We demonstrate an electrolyte-based voltage tunable vanadium dioxide (VO₂) memory metasurface. Large spatial scale, low voltage, non-volatile switching of terahertz (THz) metasurface resonances is achieved through voltage application using an ionic gel to drive the insulator-to-metal transition in an underlying VO₂ layer. Positive and negative voltage application can selectively tune the metasurface resonance into the "off" or "on" state by pushing the VO₂ into a more conductive or insulating regime respectively. Compared to graphene based control devices, the relatively long saturation time of resonance modification in VO₂ based devices suggests that this voltage-induced switching originates primarily from electrochemical effects related to oxygen migration across the electrolyte-VO₂ interface.