Reverse flux of energy of a nonparaxial optical vortex in the near field

Abstract

In this work, using an expansion in terms of plane waves, we obtain all six components of the electric and magnetic field vectors for an elliptically polarized optical vortex with an arbitrary integer topological charge. We also obtain expressions for the distributions of the field intensity and the Poynting vector components in the initial plane of this optical vortex. For the particular case of a narrow angular spectrum of plane waves (Bessel beam) and for circular polarization, it is shown that in the presence of inhomogeneous evanescent waves in the initial light field, a reverse flux of light energy can occur near the optical axis. It is also shown that in the initial plane the effect of an “angular tractor” occurs, when at different distances from the optical axis the transverse energy flux rotates clockwise or counterclockwise. Using the obtained general expressions, the light flux for other known exact solutions of the Maxwell equations can be analyzed.