Programmable anisotropic digital metasurface for independent manipulation of dual-polarized THz waves based on a voltage-controlled phase transition of VO2 microwires†
Programmable metasurfaces incorporated with tunable materials controlled by external stimuli can provide an unprecedented degree of freedom in dynamical wave manipulation in real-time. Beyond the scope of isotropic reconfigurable metasurfaces that only support unique tunable responses for excitation with a certain single-polarization, here, for the first time a new generation ultrafast reprogrammable multi-functional anisotropic metasurface is reported to enable interchangeable functions independently for two orthogonal linearly polarized THz wavefront excitations. The reconfigurability of the proposed anisotropic meta-device was guaranteed by an elaborately designed meta-particle composed of two perpendicular VO2 microwires whose operational statuses can be arbitrarily and dynamically tuned among two digital states of “0” and “1” independently for dual-polarization channels by merely changing the biasing voltage via two independent computer-programmed multichannel DC networks. Capitalizing on such meta-particle design furnishes an inspiring platform to manipulate the far-field scattering patterns and near-field behavior in each desired polarization channel. The anisotropic meta-device brings new degrees of freedom in achieving versatile tunable control of differently polarized electromagnetic waves, which will significantly enhance storage density and data capacities and has the potential for complicated wave manipulation such as ultrafast THz communication and dynamic holography.