Directional acoustic emission via topological insulators based on cavity-channel networks

Abstract

In this paper, directional acoustic emission via topological insulators is investigated. For this purpose, a topological insulator based on a cavity-channel network is constructed, and the band structure of this topological insulator is studied theoretically and numerically. Topologically protected edge states between the topological insulators are numerically demonstrated. Directional emission with a half-power angular width as narrow as 5° can be achieved via the topological surface, which is composed of a few layers of topological insulators. This device, based on the topologically protected edge state, shows robustness to defects. This work shows the potential for making robust and tunable acoustic emission devices.