All-optical generation of surface plasmons in graphene
All-optical generation of surface plasmons in graphene
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DOI：
10.1038/nphys3545
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发表时间：
2016-02-01
期刊：
影响因子：
19.6
通讯作者：
Hendry, E.
中科院分区：
文献类型：
--
作者：
Constant, T. J.;Hornett, S. M.;Hendry, E.
石墨烯中的表面等离子体为许多有用的光子技术提供了一条引人注目的路线（1-3）。作为一种等离子体材料，石墨烯提供了几个有趣的特性，例如优异的电光可调谐性（4）、晶体稳定性、大的光学非线性（5）和极高的电磁场浓度（6）。因此，最近使用红外光的近场散射的石墨烯中的表面等离子体激元激发的演示（7，8）已经引起了强烈的兴趣。在这里，我们提出了一个全光等离子体激元耦合方案，利用石墨烯的固有非线性光学响应。自由空间可见光脉冲用于使用差频波混合在平面石墨烯片中产生表面等离子体激元，以匹配表面波的波矢量和能量。通过仔细控制相位匹配条件，我们发现可以在很大的频率范围内激发具有确定波矢和方向的表面等离子体，在我们的实验中估计的光子效率接近10（-5）。
Surface plasmons in graphene offer a compelling route to many useful photonic technologies(1-3). As a plasmonic material, graphene offers several intriguing properties, such as excellent electro-optic tunability(4), crystalline stability, large optical nonlinearities(5) and extremely high electromagnetic field concentration(6). As such, recent demonstrations of surface plasmon excitation in graphene using near-field scattering of infrared light(7,8) have received intense interest. Here we present an all-optical plasmon coupling scheme which takes advantage of the intrinsic nonlinear optical response of graphene. Free-space, visible light pulses are used to generate surface plasmons in a planar graphene sheet using difference frequency wave mixing to match both the wavevector and energy of the surface wave. By carefully controlling the phase matching conditions, we show that one can excite surface plasmons with a defined wavevector and direction across a large frequency range, with an estimated photon effciency in our experiments approaching 10(-5).