Reverse canonical energy flow at the sharp focus of vector laser beams

Employing the Richards-Wolf formalism that adequately describes an electromagnetic field near the sharp focus of an ideal spherical lens, we demonstrate that certain light fields (linearly polarized optical vortex, cylindrical vector fields of an arbitrary order) have a reverse canonical energy flow in the focus plane. When the numerical aperture is 0.95, maximal magnitude of the reverse energy flow amounts to nearly 0.7% of the maximal magnitude of the direct energy flow. The distribution of the reverse canonical flow in the focus plane can have the shape of concentric rings or only arcs of the concentric rings. For certain light fields, for instance, for an azimuthally polarized light field, the longitudinal component of the canonical energy flow vector coincides with the longitudinal component of the Poynting vector. It is shown that a circularly polarized optical vortex does not have the reverse flow at the focus.