Acoustic Geometric-Phase Meta-Array

TL;DR

This paper introduces an acoustic geometric-phase meta-array that uses orbital angular momentum conversion to control acoustic waves, extending optical geometric-phase metasurface concepts to acoustics for advanced wave manipulation.

Contribution

It presents a novel acoustic meta-array design leveraging orbital angular momentum conversion, enabling geometric-phase control in acoustics, which was previously limited due to the lack of spin in acoustic waves.

Findings

Demonstrates control over acoustic wavefronts using geometric-phase principles.

Extends optical metasurface concepts to acoustic wave manipulation.

Provides a new method for acoustic wave control through topological charge conversion.

Abstract

Metasurfaces based on geometric phase acquired from the conversion of the optical spin states provide a robust control over the wavefront of light, and have been widely employed for construction of various types of functional metasurface devices. However, this powerful approach cannot be readily transferred to the manipulation of acoustic waves because acoustic waves do not possess the spin degree of freedom. Here, we propose the concept of acoustic geometric-phase meta-array by leveraging the conversion of orbital angular momentum of acoustic waves, where well-defined geometric-phases can be attained through versatile topological charge conversion processes. This work extends the concept of geometric-phase metasurface from optics to acoustics, and provides a new route for acoustic wave control.