Transmissive terahertz metasurfaces with vanadium dioxide split-rings and grids for switchable asymmetric polarization manipulation

Abstract

Abstract Metasurfaces containing arrays of thermally tunable metal-free (double-)split-ring meta-atoms and metal-free grids made of vanadium dioxide (VO $$_2$$ 2 ), a phase-change material can deliver switching between (1) polarization manipulation in transmission mode as well as related asymmetric transmission and (2) other functionalities in the terahertz regime, especially when operation in the transmission mode is needed to be conserved for both phases of VO $$_2$$ 2 . As the meta-atom arrays function as arrays of metallic subwavelength resonators for the metallic phase of VO $$_2$$ 2 , but as transmissive phase screens for the insulator phase of VO $$_2$$ 2 , numerical simulations of double- and triple-array metasurfaces strongly indicate extreme scenarios of functionality switching also when the resulting structure comprises only VO $$_2$$ 2 meta-atoms and VO $$_2$$ 2 grids. More switching scenarios are achievable when only one meta-atom array or one grid is made of VO $$_2$$ 2 components. They are enabled by the efficient coupling of the geometrically identical resonator arrays/grids that are made of the materials that strongly differ in terms of conductivity, i.e. Cu and VO $$_2$$ 2 in the metallic phase.