Multifunctional acoustic holography based on compact acoustic geometric-phase meta-array

TL;DR

This paper introduces a novel acoustic meta-atom design that utilizes acoustic geometric phase for multifunctional acoustic holography, enabling advanced control and reconstruction of acoustic fields.

Contribution

It pioneers the concept of acoustic geometric-phase modulation using deep subwavelength meta-atoms, expanding acoustic meta-array capabilities for holography and field engineering.

Findings

Achieved tunable acoustic geometric-phase modulation.

Demonstrated high-quality acoustic field reconstruction.

Enabled multifunctional acoustic meta-holograms.

Abstract

Optical geometric-phase metasurface provides a robust and efficient means for light control by simply manipulating the spatial orientations of the in-plane anisotropic meta-atoms, where polarization conversion plays a vital role. However, the concept of acoustic geometric-phase modulation for acoustic field control remains unexplored because airborne acoustic waves lack a similar optical polarization conversion process. In this work, a new type of acoustic meta-atom with deep subwavelength feature size is theoretically investigated and further applied to acoustic field engineering based on the so-called acoustic geometric phase. Herein, tunable acoustic geometric-phase modulation of designated order is obtained via the near-field coupled orbital angular momentum transfer process, and the topological charge-multiplexed acoustic geometric phase endows our meta-arrays with multiple functionalities. Our work extends the capacity of acoustic meta-arrays in high-quality acoustic field reconstruction and offers new possibilities in multifunctional acoustic meta-holograms.