Spatiotemporal Magnonic Vortex Beams with Alternating Transverse Orbital Angular Momentum

TL;DR

This paper reports the discovery of spatiotemporal magnonic vortex beams in a ferromagnetic nanostrip, featuring alternating transverse orbital angular momentum and zigzag wave propagation, expanding the understanding of vortex beams beyond photonics and acoustics.

Contribution

It introduces the first observation of spatiotemporal magnonic vortex beams with alternating transverse orbital angular momentum in a confined geometry.

Findings

Magnonic vortex beams contain immobile phase dislocations.

Wave propagates in a zigzag-like route.

Transverse orbital angular momenta are spatially alternating.

Abstract

Recent theoretical and experimental studies revealed spatiotemporal photonic, and acoustic, vortex beams in open space. The spatiotemporal vortex beams carry orbital angular momentum perpendicular to the wave propagation direction. Here, we report spatiotemporal magnonic vortex beams in a confined geometry of a ferromagnetic nanostrip. The spatiotemporal magnonic vortex beam contains immobile phase dislocations and the wave propagates in a zigzag-like route. It is remarkable that the transverse orbital angular momentums, carried by the phase dislocations, are spatially alternating. Our findings are in sharp contrast to the photonic and acoustic counterparts, and open a new area in the study of spatiotemporal vortex beams.