Dynamics of the dislocation reactions and optical self-recovering: single-axis crystals

It is commonly supposed that optical vortices (screw or edge wavefront dislocations) are generated either by natural or artificial phase nonuniformity located on a light beam guide (or inside a laser cavity). A nonuniformly polarized beam is regarded as a field with a fine wave structure, bearing vector singularities such as disclinations, C-lines and L-surfaces without connection with optical vortices. Nevertheless, the fine polarization field structure can be transformed under certain conditions into typical phase singularities - optical vortices and vice versa. Moreover, the energy efficiencies of these transformations are considerably higher and constructions of corresponding devices are much simpler than those connected with the usual vortex generation. The aim of the given paper is an experimental and theoretical study of the singular field structure of a light beam in a single-axis crystal in order to reveal the physical mechanisms of polarization and phase transformations.