Abstract

Helical laser beams, often referred to as vortex beams or the beams with a phase singularity on the beam axis, have been constantly attracting researchers interest last years because of their "doughnut" intensity distribution and nonzero values of topological charge and orbital angular momentum. All these features can be useful in a number of applications. Usually laser beams with helical wavefronts are obtained via diffraction of conventional laser beams on computer-generated holograms [1] or with the use of cylindrical lens converters [2]. Such converters can transform the Hermite-Gaussian beams into Laguerre-Gaussian ones that have the nonzero topological charge. However these techniques have limited usefulness in generating high-power helical beams that are of interest in connection with investigation of vortex solitons in nonlinear media and in some other applications.

© 2000 IEEE