Acoustic topological systems explore topological behaviors of phononic crystals. Currently, most of the experimentally demonstrated acoustic topological systems are for airborne acoustic waves and work at or below the kHz frequency range. Here, we report an underwater acoustic topological waveguide that works at the MHz frequency range. The 2D topological waveguide was formed at the interface of two hexagonal lattices with different pillar radii that were fabricated with metal additive manufacturing. We demonstrated the existence of edge stages both numerically and in underwater experiments. Our work has potential applications in underwater/biomedical sensing, energy transport, and acoustofluidics.
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Dispersion tuning and route reconfiguration of acoustic waves in valley topological phononic crystals
The valley degree of freedom in crystals offers great potential for manipulating classical waves, however, few studies have investigated valley states with complex wavenumbers, valley states in graded systems, or dispersion tuning for valley states. Here, we present tunable valley phononic crystals (PCs) composed of hybrid channel-cavity cells with three tunable parameters. Our PCs support valley states and Dirac cones with complex wavenumbers. They can be configured to form chirped valley PCs in which edge modes are slowed to zero group velocity states, where the energy at different frequencies accumulates at different designated locations. They enable multiple functionalities, including tuning of dispersion relations for valley states, robust routing of surface acoustic waves, and spatial modulation of group velocities. This work may spark future investigations of topological states with complex wavenumbers in other classical systems, further study of topological states in graded materials, and the development of acoustic devices.
more » « less- PAR ID:
- 10153310
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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