Damping pathways of mid-infrared plasmons in graphene nanostructures
Damping pathways of mid-infrared plasmons in graphene nanostructures
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DOI：
10.1038/nphoton.2013.57
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发表时间：
2013-05-01
期刊：
影响因子：
35
通讯作者：
Xia, Fengnian
中科院分区：
文献类型：
--
作者：
Yan, Hugen;Low, Tony;Xia, Fengnian
等离子体激元是电子集体振荡的量子。等离激元如何失去能量（或阻尼）在等离激元科学和技术中起着关键作用。石墨烯等离子体激元特别令人感兴趣，部分原因是其潜在的低阻尼率。然而，迄今为止，阻尼途径尚未通过实验明确阐明。在这里，我们展示了尺寸小至 50 nm 的石墨烯纳米结构中的中红外（4-15 μ m）等离子体激元（模式面积类似于 1x10(-3) μ m(2)）。我们还通过石墨烯固有光学声子和边缘散射揭示了阻尼通道。当允许通过石墨烯光学声子发射进行阻尼时，观察到 20 fs 或更短的等离子体激元寿命。此外，与非极性类金刚石碳基底的情况相比，石墨烯纳米结构下的 SiO2 基底中的表面极性声子导致等离激元色散和阻尼显着改变。我们的研究为石墨烯在亚太赫兹到中红外区域的等离子体波导、调制器和探测器中的应用铺平了道路。
Plasmon is the quantum of the collective oscillation of electrons. How plasmon loses its energy (or damping) plays a pivotal role in plasmonic science and technology. Graphene plasmon is of particular interest, partly because of its potentially low damping rate. However, to date, damping pathways have not been clearly unravelled experimentally. Here, we demonstrate mid-infrared (4-15 mu m) plasmons in graphene nanostructures with dimensions as small as 50 nm (with a mode area of similar to 1x10(-3) mu m(2)). We also reveal damping channels via graphene intrinsic optical phonons and scattering from the edges. Plasmon lifetimes of 20 fs or less are observed when damping via the emission of graphene optical phonons is allowed. Furthermore, surface polar phonons in the SiO2 substrate under graphene nanostructures lead to a significantly modified plasmon dispersion and damping, in contrast to the case of a nonpolar diamond-like-carbon substrate. Our study paves the way for applications of graphene in plasmonic waveguides, modulators and detectors from sub-terahertz to mid-infrared regimes.