Generation of optical vortices in layered helical waveguides

Abstract

We study the possibility of changing the topological charge of incident beams by layered helical structures consisting of planar layers. We show that such structures can effectively change the topological charge of the incoming beam by unity. The problem of the fundamental mode and optical vortex passage through such a layered helical waveguide of a finite length is solved. The spectral characteristics of these processes are obtained. It is shown that such a waveguide can operate as a broadband compact generator of optical vortices from both regular and singular beams.