The set of works is devoted to the investigation of optical singularities which are the special points of an electromagnetic field, where so-called optical vortices appear being able to carry orbital angular momentum of light. The structure of transversal optical vortices and processes (topological reactions) which take place in a light field were investigated. The theoretical analysis was performed for waves created by the binary computer-generated holograms that contain optical vortices with a fractional topological charge. The problem of quantization of a photon orbital angular momentum projection was first solved. It was shown that if the optical beam rotates (or in general moves periodically) its spectrum of orbital angular momentum generates the proper frequency spectrum. The investigation of phase velocity of light in a shadow area during diffraction of plane wave on an opaque disk was also performed. Superluminal wave-front propagation in the geometrical shadow zone (Poisson’s spot) behind the disk was observed and explained. The scope of obtained results complements the existent knowledge about fundamental nature of light and has large prospects in practical applications.