Optical forces and torques in skyrmionic beams

Freely propagating, purely optical skyrmions may be generated from combinations of vector beams with orthogonal polarisation states. Through this approach it is possible to create skyrmions of both Néel (hedgehog) and Bloch (spiral) types, using both paraxial [Gao et al. Phys. Rev. A, 102, 053513 (2020)] and focussed Laguerre-Gaussian beams [Gutiérrez-Cuevas and Pisanty, J. Opt. 23, 024004 (2021)]. In this computational study we construct skyrmionic beams with different skyrmion numbers and types with a view to analysing the spin and orbital angular momentum fluxes carried by the beams. The optical forces and torques experienced by dielectric and absorbing particles are calculated and their dynamic behaviour assessed.