Hole-Embedded Graphene Metamaterial for THz Absorption: A New Approach for Efficient Device Design

Abstract

Abstract A new design is proposed for the realization of graphene metamaterials with enhanced robustness and absorption in the THz regime. The design uses the concept of embedding holes into a bilayer graphene sheet, which effectively works like a conventional fishnet-shaped metamaterial structure with better absorptance and spectral response features. Absorptance of both the structures are studied for multi-sheet configuration with sheet number (N), inter sheet distance (dil), and length of the resonating cavity (d). Interestingly the absorptance goes up with an increase in N for both the structures. Further, in the case of the proposed hole embedded structure, the rate of enhancement is more towards the higher N indicating improved performance. The study also reveals the effect of cavity length ‘d’ on absorptance. The absorptance of the metamaterials is optimized to a value of ~ 99%, for d = 22 µm, taking N = 8 and N = 7 for the cut-based and the hole embedded fishnet structure respectively. The proposed hole embedded design offers several benefits like it reduces design complexity, increases the robustness towards fabrication errors, needs less number of sheets, and shows a better spectral response. Such a design technique can be utilized to realize several other designs of meta materials.