THE GAUSSIAN LENSES GIVE BIRTH TO OPTICAL VORTICES IN LASER-BEAMS

It is shown theoretically that Gaussian-like lenses initiate birth, ev olution and annihilation of the phase singularities in coherent beams with initially smooth wavefront. The stigmatic lens originates circula r edge dislocation, which disappears immediately. The astigmatic Gauss ian lenses give birth to quadrupoles of opposite single-charged optica l vortices. The optical vortices move in space along a closed trajecto ry, the more stretched the greater is the lens astigmatism. The develo ped model gives the complete scenario of the optical singularities ori gin and evolution, and describes naturally all experimentally observed features for known light-induced Gaussian-like nonlinear lenses. (C) 1998 Elsevier Science B.V.