Active metasurfaces composed of electrically reconfigurable nanoscale subwavelength antenna arrays can enable real-time control of scattered light amplitude and phase. Achievement of widely tunable phase and amplitude in chip-based active metasurfaces operating at or near 1550 nm wavelength has considerable potential for active beam steering, dynamic hologram rendition, and realization of flat optics with reconfigurable focal lengths. Previously, electrically tunable conducting oxide-based reflectarray metasurfaces have demonstrated dynamic phase control of reflected light with a maximum phase shift of 184° ( Nano Lett. 2016, 16, 5319). Here, we introduce a dual-gated reflectarray metasurface architecture that enables much wider (>300°) phase tunability. We explore light-matter interactions with dual-gated metasurface elements that incorporate two independent voltage-controlled MOS field effect channels connected in series to form a single metasurface element that enables wider phase tunability. Using indium tin oxide (ITO) as the active metasurface material and a composite hafnia/alumina gate dielectric, we demonstrate a prototype dual-gated metasurface with a continuous phase shift from 0 to 303° and a relative reflectance modulation of 89% under applied voltage bias of 6.5 V.

中文翻译：

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双栅极有源超颖表面在1550 nm处具有宽（> 300°）相位可调性

由电可重构纳米级亚波长天线阵列组成的有源超表面可以实现对散射光幅度和相位的实时控制。在波长为1550 nm或接近1550 nm的基于芯片的有源超颖表面上实现可广泛调谐的相位和幅度，对于有源光束转向，动态全息图再现以及实现具有可重新配置焦距的平面光学器件具有巨大的潜力。反射的光的前面，电可调导电氧化物基反射阵列metasurfaces已经证明动态相位控制与184°（的最大相移纳米快报。 2016，16，5319）。在这里，我们介绍了一种双门反射阵列超表面结构，该结构可实现更宽（> 300°）的相位可调性。我们探索了与双门控超颖表面元件的光-质相互作用，该双栅极超颖表面元件结合了两个独立的电压控制的MOS场效应通道，这些沟道串联在一起，形成了单个超颖表面元件，从而实现了更宽的相位可调性。使用铟锡氧化物（ITO）作为活性超表面材料和复合氧化f /氧化铝栅极电介质，我们演示了原型双栅极超表面，其在0至303°的范围内连续相移，并且在施加电压下的相对反射率调制为89％ 6.5 V的偏压