A triply periodic minimal surface-based acoustic crystal with double-zero index

Area of Science:

• Acoustics
• Materials Science
• Physics

Background:

• Three-dimensional (3D) acoustic crystals (ACs) with a double-zero index offer unique properties for acoustic wave manipulation.
• Conventional 3D double-zero-index ACs face fabrication challenges due to disconnected solid structures.

Purpose of the Study:

• To propose a fabrication-friendly 3D acoustic crystal with a double-zero index using triply periodic minimal surfaces (TPMS).
• To demonstrate the acoustic wave cloaking and tunneling functionalities of the proposed TPMS-based AC.
• To investigate the tunable mechanical properties of the novel structure.

Main Methods:

• Fabrication of a TPMS-based acoustic crystal exhibiting a double-zero index.
• Accidental degeneracy of a Dirac-like cone by three dipolar and one monopolar modes.
• Experimental characterization of acoustic wave tunneling and cloaking.
• Evaluation of mechanical properties.

Main Results:

• Successful fabrication of a TPMS-based 3D acoustic crystal with a double-zero index.
• Experimental demonstration of acoustic wave tunneling and cloaking functionalities.
• Tunable mechanical properties were observed in the TPMS-based AC.
• The structure overcomes fabrication limitations of traditional designs.

Conclusions:

• The developed TPMS-based AC provides a fabrication-friendly approach to achieving double-zero-index properties.
• This novel structure enables advanced acoustic functionalities like cloaking and tunneling.
• The superior mechanical performance and fabrication ease pave the way for multifunctional acoustic devices.