Optical vortex sign determination using self-interference methods

Abstract

Optical vortices are singular lines in a phase distribution of a light field. Usually they are observed in planar cross section (on the screen) as dark points with undefined phase (vortex points) [1–3]. The wavefront takes characteristic helical form in the vicinity of the vortex line (Fig. 1) [1–4]. The twisted helical wavefront results a non-zero angular momentum carried by the beam with the optical vortex [3]. The wavefront’s helical geometry allows for vortex classification due to the helice handedness. We say that optical vortex may have