Generalized momentum conservation and Fedorov-Imbert linear shift of acoustic vortex beams at a metasurface

Wei Wang, Yang Tan, Bin Liang*, Guancong Ma, Shubo Wang, Jianchun Cheng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

We study the transmission and reflection of a paraxial acoustic vortex beam (AVB) at a metasurface with a prescribed phase gradient. By using a plane-wave decomposition method, we obtain a closed-form expression for the transverse shift of the beam's gravity center. The transverse shift is proportional to the topological charge of the AVB and derives from momentum conservation and the reflection/transmission coefficient modulation. It corresponds to the acoustic Fedorov-Imbert linear shift and represents the orbital Hall effect for spinless longitudinal sound. We develop a generalized momentum conservation relation to understand the phenomena and find that the metasurface induces both linear momentum and angular momentum, which have different dependences on the incident angle. In particular, this mechanism can enable the Fedorov-Imbert linear shift even for normal incidence and total reflection. The results provide deeper insights into the physics underlying the interaction of AVBs with metasurfaces and may help the development of orbital angular momentum based acoustic devices.

Original languageEnglish
Article number174301
JournalPhysical Review B
Volume104
Issue number17
DOIs
Publication statusPublished - 1 Nov 2021

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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