一种基于石墨烯超材料的可调太赫兹吸波体

A Tunable Absorber Based on Graphene Metamaterial

设计了一种在太赫兹频段具有多模可调特性的石墨烯超材料吸波体。这种超材料吸波体由石墨烯-金的阻抗表面、石墨烯层、Si O2基板以及金的反射底板构成。石墨烯层和石墨烯阻抗表面的化学势可独立调节,从而大大提高了调节的灵活性。运用等效电路分析法和场分析方法对其吸波机理进行分析。从数值计算的结果来看,该吸波体在2.4THz, 4.2THz和7.2THz具有三种吸波模式,每一种模式都可以实现完美吸波(≥99.2%)。在化学势的调节下,该吸波体可实现模式内吸波频率可调以及模式间调节,在不改变物理结构的前提下实现单频带吸波和双频带吸波的转化。

In this paper, a novel design of metamaterial absorber(M A) with mode tunability characteristic in THz range is presented. The MA consists of patterned gold-graphene on the top layer, graphene sheet and gold ground separated by SiO2. The chemical potential of patterned gold-graphene and graphene sheet can be tuned independently so the modulation flexibility of M A is greatly enhanced. For demonstration, the proposed M A is investigated using circuit analogy method and the distributions of the electric field are also discussed in details to explore underlying mechanism. Numerical results are stimulated in a commercial full-wave solver and indicate that the proposed M A possesses excellent absorption properties. There are three resonant modes with absorption peaks at 2.2TH, 4.2 THz and 7.2THz respectively and could achieve near perfect absorption(≥99.2%) in each mode. Under the modulation of chemical potential of both patterned gold-graphene and graphene sheet, the proposed M A could serve as single-and dual-frequency absorber respectively without change of physical structure.