Spatiotemporal Vortex Pulses: Angular Momenta and Spin-Orbit Interaction

TL;DR

This paper provides a comprehensive theoretical analysis of spatiotemporal optical vortex pulses, detailing their angular momentum properties, polarization, and spin-orbit interactions, and extends the analysis to other types of vortex pulses.

Contribution

It offers the first detailed theoretical framework for scalar and vector spatiotemporal vortex pulses, including calculations of local and integral angular momenta and predictions of observable spin-orbit effects.

Findings

Calculated local and total spin and orbital angular momenta.

Predicted observable spin-orbit interaction phenomena.

Extended analysis applicable to other vortex pulse types.

Abstract

Recently, spatiotemporal optical vortex pulses carrying a purely transverse intrinsic orbital angular momentum were generated experimentally [{\it Optica} {\bf 6}, 1547 (2019); {\it Nat. Photon.} {\bf 14}, 350 (2020)]. However, an accurate theoretical analysis of such states and their angular-momentum properties remains elusive. Here we provide such analysis, including scalar and vector spatiotemporal Bessel-type solutions as well as descrption of their propagational, polarization, and angular-momentum properties. Most importantly, we calculate both local densities and integral values of the spin and orbital angular momenta, and predict observable spin-orbit interaction phenomena related to the coupling between the trasnverse spin and orbital angular momentum. Our analysis is readily extended to spatiotemporal vortex pulses of other natures (e.g., acoustic).