Robust Acoustic Waveguide Transport in Heterostructures Based on Acoustic Topological Insulators

Topological insulators have attracted great interest in recent years because of their robust transports of topological boundary states. Usually, the topological boundary states are sharply localized at the boundaries, which limits the capacity of transmissions and the interfacing with existing bulk devices in applications. Here, based on the acoustic topological insulators with pseudospin, we realize topological heterostructures that host a pair of helical waveguide modes. With the freedom of width, the waveguide modes are of adjustable capacity of transmissions, and convenient for applications. The waveguide modes are revealed to be robust against disorders and structural defects. We also demonstrate the partition and beam collimation of the topological waveguide modes. These results pave a way to explore the topological transports in versatile designs of heterostructures for acoustic waves.