Topological phononic waveguide design on surface of 3D object

Abstract

Phononic crystals are artificial structures in which materials with different acoustic properties are periodically arranged. In conventional acoustic waveguides using phononic crystals, scattering occurs at defects and bends in the waveguide, resulting in large transmission losses. Recently, by applying the concept of topology to the band structure of phononic crystals, topologically protected wave propagations have been shown to be possible. In this study, we designed a waveguide on the surfaces of 3-dimensional objects. We show that sound waves travel multiple times along the same trajectory by arranging topological phononic crystals on the curved surfaces.