Horn-like space-coiling metamaterials toward simultaneous phase and amplitude modulation.

Area of Science:

• Acoustics
• Materials Science
• Wave Physics

Background:

• Acoustic metasurfaces are planar devices for manipulating acoustic waves.
• Current metasurfaces primarily focus on phase modulation, neglecting amplitude control.
• Precise geometric tailoring of metasurfaces allows for modulation of effective refractive index and acoustic phase delays.

Purpose of the Study:

• To introduce a new class of acoustic metasurfaces capable of simultaneous phase and amplitude modulation.
• To investigate the functionality of these metasurfaces theoretically and numerically.
• To experimentally validate the performance of a designed metasurface for acoustic radiation pattern modification.

Main Methods:

• Design of metasurfaces featuring a horn-like space-coiling structure with gradient channel spacing.
• Theoretical analysis and numerical simulations to understand the acoustic control capabilities.
• Experimental fabrication and testing of a metasurface to validate its performance in modifying acoustic radiation patterns.

Main Results:

• Demonstration of acoustic metasurfaces enabling simultaneous phase and amplitude modulation.
• Presentation of an equivalent model that simplifies the behavior of the space-coiling metasurfaces.
• Experimental validation of the designed metasurface's ability to alter acoustic radiation patterns.

Conclusions:

• This novel class of acoustic metasurfaces provides a comprehensive approach to acoustic wave manipulation.
• The developed design methodology is efficient and enables complete control over acoustic waves.
• Potential applications include biomedical imaging, acoustic communication, and non-destructive testing.