Reconfigurable acoustic vortex via a 3D reflective metagrating

Abstract

Acoustic vortices carrying orbital angular momentum, often generated using metagratings, provide an effective approach for wavefront engineering, particle manipulation, and underwater information transfer. However, most existing acoustic metagratings rely on fixed structural configurations, which inherently restrict their tunability and multifunctionality. Here, we propose a three-dimensional reconfigurable reflective acoustic metagrating for dynamic manipulation of vortex fields. The device consists of two gradient-depth air-groove supercells, in which the reflection response can be actively reconfigured by tuning the depth of paired grooves. Based on a generalized conservation principle of topological charge in metagrating diffraction, we demonstrate controllable conversion of incident acoustic vortex beams into reflected vortex states with different diffraction channels. In particular, near-perfect switching between anomalous reflection and specular reflection is achieved with high conversion efficiency. In addition to structural reconfiguration, frequency-dependent modulation provides an additional degree of freedom for dynamically tailoring the reflected vortex field. Our results reveal a simple yet robust mechanism for tunable vortex-beam reflection and offer a compact platform for multifunctional acoustic devices, with potential extensions to other wave systems such as electromagnetic and elastic waves.

Keywords

acoustic vortex / reconfigurable metagrating / orbital angular momentum / topological charge

RIGHTS & PERMISSIONS

Higher Education Press 2026

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