Extended Data Fig. 6: Topological properties of plasmonic vortex system.

a, L-line map of a 2 μm × 2 μm region about the central vortex. The central domains are surrounded by apple-shaped toroids that are delimited by dashed lines and repeat with an approximate periodicity of λ_SPP (along the y direction) to infinity. Different domains of interest are coloured and labelled with the corresponding topological charge. Black dots mark the phase singularities, within these regions. b, Normalized spin texture overlapped by the L-line map in a. The colour map and arrows indicate the spin components, as in Supplementary Fig. 3b. c, d, Enlarged spin textures at side phase singularities indicated by the square shading in c. e, f, Spin texture in the same region as in c, d, but with the sign of positive S_z reversed, while conserving the topological charge. Black dots in c, d indicate positions of the phase singularities.