Probing graphene's nonlocality with singular metasurfaces
Probing graphene's nonlocality with singular metasurfaces
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DOI：
10.1515/nanoph-2019-0323
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发表时间：
2020-02-01
期刊：
影响因子：
7.5
通讯作者：
Pendry, John B.
中科院分区：
文献类型：
--
作者：
Galiffi, Emanuele;Huidobro, Paloma A.;Pendry, John B.
最近提出了通过周期性地抑制石墨烯片的局部掺杂水平来实现的奇异石墨烯超颖表面、导电性光栅，以有效地捕获THz光并将其耦合到宽吸收带上的表面等离子体，从而实现显著高的场增强。然而，由此获得的大动量波矢对底层电子液体的非局域行为敏感。在这里，我们扩展了奇异石墨烯超颖表面的理论，以解释石墨烯的完整非局域光学响应，并讨论了由此产生的对等离子体共振光谱的影响。最后，我们提出了一个简单的局部模拟模型，该模型能够通过引入恒定的电导率偏移来再现局部响应计算中的非局部性效应，这可以证明在更复杂的实验石墨烯平台的建模中是一个有价值的工具。
Singular graphene metasurfaces, conductivity gratings realized by periodically suppressing the local doping level of a graphene sheet, were recently proposed to efficiently harvest THz light and couple it to surface plasmons over broad absorption bands, thereby achieving remarkably high field enhancement. However, the large momentum wavevectors thus attained are sensitive to the nonlocal behavior of the underlying electron liquid. Here, we extend the theory of singular graphene metasurfaces to account for the full nonlocal optical response of graphene and discuss the resulting impact on the plasmon resonance spectrum. Finally, we propose a simple local-analogue model that is able to reproduce the effect of nonlocality in local-response calculations by introducing a constant conductivity offset, which could prove a valuable tool in the modeling of more complex experimental graphene-based platforms.