Metamaterials bring subwavelength resonating structures together to overcome the limitations of conventional materials. 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. However, the existing capability of metamaterials is not sufficient to realize this goal. By integrating passive metamaterials with active graphene devices, we demonstrate a new class of electrically controlled active metadevices working in microwave frequencies. The fabricated active metadevices enable efficient control of both amplitude (>50 dB) and phase (>90°) of electromagnetic waves. In this hybrid system, graphene operates as a tunable Drude metal that controls the radiation of the passive metamaterials. Furthermore, by integrating individually addressable arrays of metadevices, we demonstrate a new class of spatially varying digital metasurfaces where the local dielectric constant can be reconfigured with applied bias voltages. In addition, we reconfigure resonance frequency of split-ring resonators without changing its amplitude by damping one of the two coupled metasurfaces via graphene. Our approach is general enough to implement various metamaterial systems that could yield new applications ranging from electrically switchable cloaking devices to adaptive camouflage systems.

中文翻译：

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通过石墨烯可电切换的元设备。

超材料将亚波长谐振结构整合在一起，以克服常规材料的局限性。有源元设备的实现一直是一项艰巨的挑战，需要在宽范围内以宽动态范围运行的电气可重配置组件。但是，超材料的现有能力不足以实现这一目标。通过将无源超材料与有源石墨烯设备集成在一起，我们演示了在微波频率下工作的一类新型电控有源超设备。所制造的有源元设备能够有效控制电磁波的幅度（> 50 dB）和相位（> 90°）。在这种混合系统中，石墨烯用作可调节的Drude金属，可控制无源超材料的辐射。此外，通过集成可单独寻址的元设备阵列，我们演示了新型的空间变化的数字元表面，其中可以通过施加偏置电压来重新配置局部介电常数。另外，我们通过阻尼通过石墨烯的两个耦合的超颖表面之一来重新配置开环谐振器的谐振频率，而不改变其振幅。我们的方法足够通用，可以实现各种超材料系统，这些系统可以产生新的应用，从可电气开关的隐身设备到自适应伪装系统。我们通过通过石墨烯阻尼两个耦合的超颖表面之一来重新配置开环谐振器的谐振频率，而不会改变其振幅。我们的方法足够通用，可以实现各种超材料系统，这些系统可以产生新的应用，从可电气开关的隐身设备到自适应伪装系统。我们通过通过石墨烯阻尼两个耦合的超颖表面之一来重新配置开环谐振器的谐振频率，而不会改变其振幅。我们的方法足够通用，可以实现各种超材料系统，这些系统可以产生新的应用，从可电气开关的隐身设备到自适应伪装系统。