The Backflow of Energy in a Optical Vortex Formed by Silver Spiral Zone Plate

Abstract

In this paper, we theoretically investigate the generation of optical vortices by amplitude spiral zone plate made in silver film. Influence of the direction of circularly polarization of incident light on the process of vortices formation is analyzed. An investigation of the amplitude and phase distributions in the focal plane shows the presence of optical vortices with complex topological charge. Analysis of the longitudinal component of the Umov-Poynting vector shows the presence of an inverse energy flow in the focal plane.