Vortical Differential Scattering of Spatio‐Temporal Optical Vortex With Arbitrarily Oriented Orbital Angular Momentum by Chiral Spherical Particle

We theoretically investigate the vortical differential scattering (VDS) of spatiotemporal optical vortex (STOV) carrying arbitrary orbital angular momentum (OAM) orientation by chiral particles within the framework of polychromatic generalized Lorenz–Mie theory (GLMT). Numerical results show that STOVs with a nonzero longitudinal OAM component exhibit significant vortical dichroism (VD), whereas those with purely transverse OAM do not. Mechanistically, transverse OAM's zero net optical chirality density and collapsed spatial energy flow vortex lack the requisite torque and asymmetric multipolar excitations to drive chiral responses. Furthermore, it is found that the larger topological charges and tighter spatiotemporal scales significantly enhance the VD. Our work establishes a solid theoretical foundation for future explorations of the chiral dynamics of STOV, paving the way for applications in enantiomer sensing, advanced chiral spectroscopy, and precise optical manipulation.