Controlling the absorption strength in bidirectional terahertz metamaterial absorbers with patterned graphene

THz metamaterials that exhibit excellent absorption properties with real-time tunability have been of great interest for various applications. In this paper, we combine symmetric metamaterials and patterned graphene to achieve an electrically-switchable bidirectional absorption window operating in terahertz frequencies. The proposed metamaterial can homogeneously absorb the incident waves while allowing significant transmission outside the absorption band. Our simulations show that the tunable electrical conductivity of the patterned graphene can result in a desired control of the absorptivity between 41% and 91%. Finite integration simulations, standard retrieval procedure, equivalent circuit model, and effective medium analysis are employed to elaborate our idea.