Electrical control of terahertz nano antennas on VO₂ thin film

We demonstrate an active metamaterial device that allows to electrically control terahertz transmission over more than one order of magnitude. Our device consists of a lithographically defined gold nano antenna array fabricated on a thin film of vanadium dioxide (VO₂), a material that possesses an insulator to metal transition. The nano antennas let terahertz (THz) radiation funnel through when the VO₂ film is in the insulating state. By applying a dc-bias voltage through our device, the VO₂ becomes metallic. This electrically shorts the antennas and therefore switches off the transmission in two distinct regimes: reversible and irreversible switching.