Impact of the evanescent waves on the backflow of power in the near field

Abstract

Abstract For an elliptically polarized optical vortex with an arbitrary integer topological charge, using the expressions for all six components of the electric and magnetic field strength vectors, we obtain an expression for the longitudinal component of the Poynting vector in the initial plane. For the particular case of a narrow angular spectrum of plane waves (Bessel beam) and for the circular polarization, it is shown that in the presence of the inhomogeneous evanescent waves in the initial light field, a reverse flux of light energy can occur near the op-tical axis. It is shown that this reverse energy flux is due to toroidal vortices in the longitudinal plane.