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. (C)2011 Optical Society of America