Transversal optical vortex

A structure of wavefront edge dislocations and associated "transversal" optical vortices in an interference field of two two-dimensional Gaussian beams is analyzed. It was shown that the optical vortex rotation is directed toward the area of higher phase velocity in the interference field (the origin of the phase velocity variation is due to the Gouy effect). The conditions for the reversal of the sign of rotation were found as well as for annihilation of two edge dislocations. Topological reaction of "unfolding" of an edge dislocation, which happens when vortex collides with a phase saddle, is studied in details.