Photonic Band Inversion and Absorption Enhancement in Dirac Semi‐Metal Tamm Plasmon Multilayer System

Abstract Topological photonics is becoming increasingly important due to its possibility to manipulate light with topological phases. Constrained by tunable material, the concept of the topological phase of light is less employed for the realization of terahertz (THz) devices. Incorporating tunable plasmonic materials with topological photonic structures can promote topological protection at the THz frequency. Here the topological phase transition in the terahertz bands is demonstrated by integrating Dirac semi‐metal with topological photonic crystal. This work proposes photonic band inversion induced frequency splitting and absorption enhancement in bulk Dirac semi‐metal (BDS) based Tamm plasmon multilayer system. The enhancement in absorption is achieved by designing a one‐dimensional topological edge state such that the combination with the Tamm plasmon state provides topological protection to the entire BDS–photonic crystal heterostructure. The proposed structure undergoes band inversion, a topological transition in the photonic band structure. These results may facilitate the realization of terahertz topological effects and contribute to the goal of topological protection in sensing applications.