Topological edge modes enable plasmon-induced transparency in isotropic and anisotropic 2D materials

In this paper, we propose a plasmonically induced transparency (PIT) effect in 2D materials mediated by topological edge modes (TEMs). The topological PIT system consists of several units of the Su-Schrieffer-Heeger (SSH)-modeled multilayer nanoribbons coupled with a bus waveguide. Using isotropic graphene and anisotropic black phosphorus (BP) as prototypes, we demonstrate that establishing a topologically nontrivial phase enables the coexistence of bright and dark TEMs. These two modes generate a PIT spectral signature, accurately modeled by coupled mode theory. Compared to conventional PIT, our topology-driven design combines robustness with superior performance (e.g., higher Q-factors and figure of merit), while preserving topological protection against a certain degree of defect and disorders. This work presents a universal platform for designing PIT in plasmonic 2D materials, enabling topologically protected and high-performance PIT devices such as on-chip sensors.