Lorentz resonance in the homogenization of plasmonic crystals
Lorentz resonance in the homogenization of plasmonic crystals
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DOI：
10.1098/rspa.2021.0609
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发表时间：
2020-09
期刊：
影响因子：
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通讯作者：
Wei Li;R. Lipton;Matthias Maier
中科院分区：
文献类型：
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作者：
Wei Li;R. Lipton;Matthias Maier
我们解释的洛伦兹共振等离子体激元晶体，包括二维纳米介电夹杂物之间的相互作用的共振材料特性和静电性质的几何共振。这种等离子体激元晶体的一个示例是周期性地布置在非磁性体电介质内的石墨烯纳米片。我们确定的小尺度周期的长度尺度上的局部几何共振。从材料的角度来看，石墨烯表面表现出由Drude模型捕获的分散的表面电导。这些现象共同产生洛伦兹共振，其频率由表面几何形状和表面电导控制。在体元材料的有效介电张量的频率响应中发现的洛伦兹共振被示出由显式公式给出，其中材料性质和几何共振解耦。这个公式是严格的，直接从描述局部静电场的异质结构内部的校正场。我们的分析结果可以作为一个有效的计算工具来描述一般的周期性光学器件的频率依赖性。作为一个具体的例子，我们研究了两个典型的几何形状组成的纳米管和纳米带。
We explain the Lorentz resonances in plasmonic crystals that consist of two-dimensional nano-dielectric inclusions as the interaction between resonant material properties and geometric resonances of electrostatic nature. One example of such plasmonic crystals are graphene nanosheets that are periodically arranged within a non-magnetic bulk dielectric. We identify local geometric resonances on the length scale of the small-scale period. From a materials perspective, the graphene surface exhibits a dispersive surface conductance captured by the Drude model. Together these phenomena conspire to generate Lorentz resonances at frequencies controlled by the surface geometry and the surface conductance. The Lorentz resonances found in the frequency response of the effective dielectric tensor of the bulk metamaterial are shown to be given by an explicit formula, in which material properties and geometric resonances are decoupled. This formula is rigorous and obtained directly from corrector fields describing local electrostatic fields inside the heterogeneous structure. Our analytical findings can serve as an efficient computational tool to describe the general frequency dependence of periodic optical devices. As a concrete example, we investigate two prototypical geometries composed of nanotubes and nanoribbons.