Electrically Switchable Metadevices

Metamaterials bring sub-wavelength resonating structures together to overcome the limitations of conventional matter. The realization of active metadevices has been an outstanding challenge that requires electrically reconfigurable components operating over a broad spectrum with a wide dynamic range. The existing capability of metamaterials, however, is not sufficient to realize this goal. Here, integrating passive metamaterials with active graphene devices, we demonstrated a new class of electrically controlled metadevices. These metadevices enable efficient control of both amplitude (>50 dB) and phase (>90 deg.) of electromagnetic waves. In this hybrid system, graphene operates a tunable Drude metal that controls the radiation of the passive metamaterials. Furthermore, by integrating individually addressable arrays of metadevices, we demonstrated a new class of spatially varying digital metasurfaces where the local dielectric constant can be reconfigured with a bias voltage. Our approach is general enough to implement various metamaterial systems that could yield new applications ranging from electrically switchable clocking devices to adaptive camouflage systems.