Spatiotemporal Vortex Pulses: Angular Momenta and Spin-Orbit Interaction

Recently, spatiotemporal optical vortex pulses carrying a purely transverse intrinsic orbital angular momentum were generated experimentally [Optica 6, 1547 (2019); Nat. Photonics 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 description 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 transverse spin and orbital angular momentum. Our analysis is readily extended to spatiotemporal vortex pulses of other natures (e.g., acoustic).

Automated summary

Experimental generation of spatiotemporal optical vortex pulses with purely transverse intrinsic orbital angular momentum has prompted an accurate theoretical analysis, including scalar and vector spatiotemporal Bessel-type solutions and descriptions of their properties. The study calculated local densities and integral values of spin and orbital angular momenta, predicting observable spin-orbit interaction phenomena. The analysis can be extended to other types of spatiotemporal vortex pulses, such as acoustic ones.