Dual‐Band Absorption Effect in a Topological‐Insulator‐Based Tamm Plasmon Multilayer System

Topological insulator materials have attracted greater attention in recent years due to their conducting surface state and insulating bulk state. The unique surface states in topological insulators offer potential applications in photonics and optoelectronics. Herein, topological insulators’ near‐infrared plasmonic behavior is utilized to demonstrate a tunable double‐mode absorber that shows an electromagnetically induced transparency (EIT)‐like effect. A composite structure is formed by sandwiching a photonic crystal heterostructure between topological insulator layers. The transfer matrix method is used to examine the optical response. The evolution of the modes with changes in layer thicknesses, grating period number, and propagating angle is also investigated. The study is further extended to multichannel optical absorption by making changes in the composite structure period, and the resultant absorption spectrum shows a multichannel EIT‐like effect.