Broadband wide-width acoustic topological waveguides with intermittent coupling

Acoustic topological insulators (ATIs) are of great use in the reliable information transmission and processing owing to their exceptional wave modulation characteristics, such as effective backscatter suppression and defect immunity. However, energy in a topological waveguide is typically confined to a narrow region, restricting its potential for efficient energy transmission and integration with bulk devices. Moreover, the existing ATI-based waveguides with adjustable widths have narrow operating bands. Here, an acoustic topological heterostructure is proposed, supporting topological waveguides with broad bandwidths and adjustable mode widths. This heterostructure realizes intermittent coupling waveguides by alternately arranging phononic crystals with different topological properties. It not only possesses the inherent excellent robustness of topological states, but also resolves the previous trade-off between mode width and operational bandwidth. The developed heterostructure offers a pathway for designing broadband topology devices for large-scale acoustic transmission, and its mode width freedom is conducive to integration into the acoustic system. This work provides new insights into various practical applications of ATIs in multifunctional information processing, computing, and communications.