Toqeer I, Yaqoob M Z, Ghaffar A, Alkanhal Majeed A S, Khan Y, Aladadi Yosef T
J Opt Soc Am A Opt Image Sci Vis. 2021 Apr 1;38(4):465-475. doi: 10.1364/JOSAA.412649.
In this work, the theoretical study of the interaction of terahertz (THz) waves with graphene embedded into two different semi-infinite metamaterials was carried out. To model the graphene, the effective surface conductivity approach based on the Kubo formalism was used. In addition, two types of metamaterials, i.e., double-positive (DPS) and double-negative (DNG), were studied in the THz regime. The numerical modeling of metamaterials was performed in the framework of causality-principle-based Kramers-Kronig relations. The reflectance and transmittance from the graphene-embedded metamaterial structures are studied for the following four different configurations: DPS-Graphene-DPS, DPS-Graphene-DNG, DNG-Graphene-DPS, and DNG-Graphene-DNG. The influence of the chemical potential and scattering rate on the reflectance and transmittance for each configuration is analyzed. It is concluded that the DPS-Graphene-DPS and DNG-Graphene-DNG configurations behave as anti-reflectors for the THz waves, while the DPS-Graphene-DNG and DNG-Graphene-DPS configurations are suitable for THz reflector applications. Moreover, a parametric study revealed that the relative permittivity of the partnering metamaterial can be used as an additional degree of freedom to control the reflectance and transmittance of THz waves. In conclusion, the transmissive and reflective characteristics of THz waves can be controlled effectively with the appropriate choice of graphene parameters, as well as the configuration of metamaterial structures. The convergence of the analytical and numerical results is found with the published results under special conditions. The present work may have potential applications in the design of THz wave controllers, reflectors, absorbers, and anti-reflectors.
在这项工作中，开展了太赫兹（THz）波与嵌入两种不同半无限超材料中的石墨烯相互作用的理论研究。为了对石墨烯进行建模，采用了基于久保形式的有效表面电导率方法。此外，在太赫兹频段研究了两种类型的超材料，即双正（DPS）和双负（DNG）超材料。超材料的数值建模是在基于因果律原理的克拉默斯 - 克朗尼格关系框架内进行的。针对以下四种不同结构研究了嵌入石墨烯的超材料结构的反射率和透射率：DPS - 石墨烯 - DPS、DPS - 石墨烯 - DNG、DNG - 石墨烯 - DPS和DNG - 石墨烯 - DNG。分析了化学势和散射率对每种结构的反射率和透射率的影响。得出的结论是，DPS - 石墨烯 - DPS和DNG - 石墨烯 - DNG结构对太赫兹波表现为抗反射器，而DPS - 石墨烯 - DNG和DNG - 石墨烯 - DPS结构适用于太赫兹反射器应用。此外，参数研究表明，配对超材料的相对介电常数可作为控制太赫兹波反射率和透射率的额外自由度。总之，通过适当选择石墨烯参数以及超材料结构的配置，可以有效地控制太赫兹波的透射和反射特性。在特殊条件下，发现解析结果和数值结果与已发表的结果一致。本工作在太赫兹波控制器、反射器、吸收器和抗反射器的设计中可能具有潜在应用。
