Broad Electrical Tuning of Graphene-Loaded Plasmonic Antennas
Broad Electrical Tuning of Graphene-Loaded Plasmonic Antennas
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DOI：
10.1021/nl3047943
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发表时间：
2013-03-01
期刊：
影响因子：
10.8
通讯作者：
Capasso, Federico
中科院分区：
文献类型：
--
作者：
Yao, Yu;Kats, Mikhail A.;Capasso, Federico
等离子体天线能够将来自自由空间的光转换为亚波长体积，反之亦然，这有助于在纳米尺度上操纵光。动态控制天线的性能是许多应用所期望的，包括生物化学传感器、可重构超表面和紧凑的光电器件。金属结构和石墨烯的组合，其具有栅电压依赖的光学性质，正在成为电控等离子体器件的可能平台。在本文中，我们演示了在原位控制的天线使用石墨烯作为电可调负载在纳米天线间隙。在我们的实验中，我们展示了石墨烯负载天线在中红外（MIR）区域中在650 nm（类似于140 cm（-1），类似于10%的谐振频率）的宽波长范围内的电调谐。我们提出了一个等效电路模型来定量分析石墨烯负载天线对的调谐行为，并推导出谐振波长调谐范围的解析表达式。在一个单独的实验中，我们使用双谐振天线阵列实现MIR光强度调制，最大调制深度超过30%，带宽为600 nm（类似于100 cm（-1），8%的谐振频率）。这项研究表明，将石墨烯与金属纳米结构相结合提供了一条电可调光学和光电器件的途径。
Plasmonic antennas enable the conversion of light from free space into subwavelength volumes and vice versa, which facilitates the manipulation of light at the nanoscale. Dynamic control of the properties of antennas is desirable for many applications, including biochemical sensors, reconfigurable meta-surfaces and compact optoelectronic devices. The combination of metallic structures and graphene, which has gate-voltage dependent optical properties, is emerging as a possible platform for electrically controlled plasmonic devices. In this paper, we demonstrate in situ control of antennas using graphene as an electrically tunable load in the nanoscale antenna gap. In our experiments, we demonstrate electrical tuning of graphene-loaded antennas over a broad wavelength range of 650 nm (similar to 140 cm(-1), similar to 10% of the resonance frequency) in the mid infrared (MIR) region. We propose an equivalent circuit model to quantitatively analyze the tuning behavior of graphene-loaded antenna pairs and derive an analytical expression for the tuning range of resonant wavelength. In a separate experiment, we used doubly resonant antenna arrays to achieve MIR optical intensity modulation with maximum modulation depth of more than 30% and bandwidth of 600 nm (similar to 100 cm(-1), 8% of the resonance frequency). This study shows that combining graphene with metallic nanostructures provides a route to electrically tunable optical and optoelectronic devices.