Three-dimensional collimated self-accelerating beam through acoustic metascreen

Area of Science:

• Acoustics
• Metamaterials
• Wave physics

Background:

• Acoustic beams typically diverge and are limited by diffraction.
• Controlling sound wave propagation for specific applications remains a challenge.

Purpose of the Study:

• To generate three-dimensional (3D) acoustic collimated self-accelerating beams.
• To demonstrate a sourceless metascreen capable of manipulating sound wave propagation.
• To explore applications in ultrasonic imaging, diagnosis, and treatment.

Main Methods:

• Designed and fabricated a hybrid acoustic metascreen with deep subwavelength resolution.
• The metascreen combines four Helmholtz resonators and a straight pipe for efficient sound transmission and full local phase shifting.
• Applied an extra phase profile to the metascreen to tune the transmitted sound's propagation along arbitrary caustic curvatures.

Main Results:

• Successfully generated 3D acoustic collimated self-accelerating beams in the non-paraxial region.
• The metascreen demonstrated efficient sound transmission and precise phase control.
• The generated beams exhibited obstacle-bypassing and self-healing properties due to their caustic nature.

Conclusions:

• The developed acoustic metascreen offers a new method for generating self-accelerating beams.
• This technology provides a novel approach for wave manipulation with potential in advanced ultrasonic applications.
• The self-healing and obstacle-bypassing capabilities open new avenues for acoustic device design.