Reconfigurable terahertz rainbow deflector

Applied Physics Letters, Volume 118, Issue 14, April 2021. Dynamic terahertz (THz) beam steering is a promising technique for numerous applications, including communication, high-resolution imaging, and radar. However, advances in this technology are considerably limited by inadequate broadband and active phase shifters at THz frequencies. In this paper, we developed a type of VO2-based device capable of broadband THz beam steering. The effect of the tunable Brewster angle of the VO2 thin film along with the insulator-to-metal transition process was verified. We demonstrated that the VO2 grating could realize a dispersive beam deflector in a broad frequency band. Furthermore, upon heating, the VO2 grating could switch between three states of mirror reflector, “rainbow” deflector, and metallic grating. We believe that the proposed reconfigurable and broadband THz beam deflector offers a powerful avenue for manipulating THz beams.