Multiplane Diffractive Acoustic Networks.

Area of Science:

• Acoustic physics
• Wavefront engineering
• Holography

Background:

• Acoustic holograms offer precise control over pressure fields with minimal hardware.
• Applications include manipulation, fabrication, cellular assembly, and ultrasound therapy.
• Traditional acoustic holograms lack temporal control, producing static fields.

Purpose of the Study:

• To introduce a novel technique for projecting time-dynamic acoustic pressure fields.
• To develop a computational model for dynamic holograms, termed diffractive acoustic networks (DANs).
• To demonstrate the advantages of multiplane DANs over single-plane holograms.

Main Methods:

• Acoustic holograms were computationally represented as multiplane diffractive acoustic networks (DANs).
• The technique combines an input transducer array with a multiplane hologram for dynamic field projection.
• Numerical simulations and experimental validation were employed to assess DAN performance.

Main Results:

• Multiplane DANs outperform single-plane holograms in projecting complex amplitude fields.
• Increased hologram planes enhance DAN output quality for a fixed number of degrees of freedom (pixels).
• A combinatorial projector was realized, projecting more fields than transducer inputs, demonstrating pixel efficiency.

Conclusions:

• The developed diffractive acoustic network technique enables dynamic control of acoustic fields.
• Multiplane DANs offer superior performance and pixel efficiency compared to traditional holograms.
• This approach opens new possibilities for reconfigurable acoustic manipulation and advanced applications.