Orbital and spin energy flows in tight focus

Abstract

It is shown that the reverse energy flow (negative projection of the Poynting vector on the optical axis) occur in the tight focus of an optical vortex with topological charge 2 and left-hand circular polarization because the axial spin flow has a negative projection on the optical axis and is greater in magnitude than the positive projection of the orbital energy flow on the optical axis (canonical energy flow). Also, using the Richards-Wolf integral, it is shown that in the area of the reverse energy flow on the optical axis, right-hand circular polarization of light takes place, although light with left-hand circular polarization is focused.