The acoustic coupled-cavity system offers a versatile platform for exploring novel topological phenomena such as topological pumping and beyond, wherein long-range coupling, as an emerging modulation strategy, is typically introduced via extrinsic connection elements or moving fluids, resulting in increased systemic complexity or unwanted fluid-induced noise. Here, we exploit intrinsic next-nearest-neighbor (NNN) couplings within coupled-cavity systems as a controllable degree of freedom and, based on it, demonstrate a remarkable effect of asymmetric topological pumping in a compact spatially modulated acoustic lattice without extra coupling tubes and moving fluids. Through a higher-order approximation, we theoretically reveal and experimentally demonstrate that the intrinsic long-range coupling, which is commonly overlooked in previous designs, can be significantly amplified and independently modulated via rationally designing the structural parameters. As the NNN coupling increases, asymmetric band compression leads to highly uneven spectral spacings, ultimately triggering the directional breakdown of pump channels. Simulation results confirm the asymmetric pumping of sound in the spatially modulated lattices irrespective of whether nonparaxial or paraxial conditions are applied. Our findings may advance the exploration of topological phases enriched by NNN coupling and provide a design paradigm for compact acoustic devices enabling direction-selective wave control.

Close

PrevNext

View figure in article

• Acoustic metamaterials
• Acoustic wave phenomena
• Topological effects in acoustic systems
• Topological materials
• Tight-binding model