Wide Band Terahertz Switch of Undulated Waveguide With VO2 Film Coated Inner Wall

We propose a wide band terahertz (THz) switch of undulated waveguide with vanadium dioxide (VO
₂
) film coated inner wall. The forbidden bands formed by periodically undulated walls effectively restrain THz transmission when VO
₂
is in the insulator phase. An unexpected wide band appears in the transmission spectrum, connecting two forbidden bands, where metal phase VO
₂
covers the undulations and eliminates band gaps. Simulations confirm that the switch could be realized by varying the temperature in the frequency range 0.71-1.07 THz, and hence such a switch could be applied in THz systems.