Acoustic source localization in three-dimensional space based on acoustic valley-Hall topological insulators

Abstract

Acoustic valley-Hall topological insulators (VHTIs), as a kind of acoustic metamaterials, possess the attractive characteristics of both directional sound reception and regulating the propagation path of sound wave. Based on these two characteristics of acoustic VHTIs, a VHTIs-based acoustic source localization method is developed here. Firstly, the topological valley transport in the acoustic VHTIs is investigated by emitting sound to the topological interface from the routes of the entrance of the topological interface and the domain wall. We find that sound waves emitting from the entrance of the topological interface and the domain wall into the topological interface possess different angular sensitivity. Furthermore, utilizing the different angular sensitivities of the sound propagation from the two routes to the topological interface, the thin films placed at the front of the entrance of the topological interface are designed to improve the directional sound reception to a targeted sound source. The simulated and experimental results demonstrate that the half-power beamwidth can be decreased by means of placement of the film. Finally, a method of acoustic source localization by using three acoustic VHTIs is proposed and verified via experiments.