Topological Tamm edge states

In this paper, we propose a Tamm plasmon structure composed of a tungsten film and distributed Bragg reflector, which can achieve perfect absorption due to critical coupling. By tuning the thickness of the tungsten film, the reflection topology of the Tamm plasmon polariton can be manipulated, which is determined by the winding number of the reflection spectral curve in the complex plane. The interface between trivial and non-trivial surfaces supports a topological Tamm edge state, which is confined within a narrow spatial range. The simulation results based on the finite element method verify the spin-locked characteristic of the topological edge state. Our method provides a new, to our knowledge, way toward spatial control of thermal radiation by utilizing a reflection topological interface.