Graphene-Based Topological Structures for Terahertz Plasmonics

We review recent progress in the development of graphene-based topological structures for terahertz (THz) plasmonic applications. Our focus is on perforated graphene layers (PGLs), composed of coplanar graphene microribbon (GMR) arrays interconnected by graphene nanoribbon (GNR) bridges. These structures exhibit resonant plasmonic behavior and nonlinear inter-ribbon transport, enabling efficient THz detection through rectification and bolometric mechanisms. The plasmonic frequency is tunable via bias-induced carrier injection. Depending on the structural and transport parameters, the PGL devices can exhibit S-type current–voltage characteristics due to strong carrier heating and double injection feedback. Numerical analysis of the responsivity and spectral characteristics demonstrates strong resonance effects and indicates the feasibility of compact, high-performance THz sensors and photomixers based on these structures.