Acoustic spin and orbital angular momentum using evanescent Bessel beams

TL;DR

This paper analyzes the fundamental properties of acoustic evanescent Bessel beams, revealing how their spin and angular momentum depend on topological charge and frequency, with parallels to electromagnetic phenomena.

Contribution

It introduces a detailed analysis of acoustic evanescent Bessel beams' spin and orbital angular momentum, highlighting their proportionality to topological charge over frequency.

Findings

Transversal spin, canonical momentum, and orbital angular momentum are proportional to l/ω.

Complex acoustic Poynting vector and spin density show electromagnetic-like features.

Insights into acoustic angular momentum properties are provided.

Abstract

Using acoustic evanescent Bessel beam is analyzed the fundamental properties for the spin and orbital angular momentum. The calculation shows that the transversal spin, the canonical momentum, and the orbital angular momentum are proportional to the ratio $l/\omega$, where $l$ is the topological charge and $\omega$ the angular frequency. The complex acoustic Poynting vector and spin density exhibit interesting features related to the electromagnetic case.