Ultra-wide range control of topological acoustic waveguidesa)

Area of Science:

• Acoustics
• Condensed Matter Physics
• Materials Science

Background:

• Topological acoustic waveguides enable precise sound transmission.
• Current research focuses on multi-band applications, but tunable operating bands are crucial.
• Existing designs often lack simple tunability mechanisms.

Purpose of the Study:

• To develop a tunable topological acoustic waveguide with a wide control range.
• To investigate the effect of 3D resonant cavities on waveguide properties.
• To enhance the bandgap width and maintain topological robustness.

Main Methods:

• Replacing 2D resonant cavities with extended 3D resonant cavities in scatterers.
• Constructing a composite acoustic structure of 2D scatterers and 3D resonant cavities.
• Implementing a parallel resonance mechanism to widen the bandgap.

Main Results:

• Achieved continuous control of the operating frequency band via simple mechanical adjustment of 3D cavity length, with a control range of nearly 6 kHz.
• Increased bandgap width by 50% using a parallel resonance mechanism.
• Confirmed that the proposed method preserves the topological phase transition and enables high-precision, backscattering-immune unidirectional wave transmission.

Conclusions:

• The proposed composite structure offers a novel and simple method for achieving tunable topological acoustic waveguides.
• This approach provides a reliable solution for ultra-wide controllable acoustic topological components.
• The findings pave the way for advanced acoustic devices with tunable functionalities.