Enhanced vortex rotation in nonlinear refractive medium

Summary form only given. Pairs of small-core vortices in linear media have been reported to rotate at initial angular rates that are inversely proportional to the square of the pair separation distance. These rates can be orders of magnitude greater than those for large-core vortices. This linear phenomenon was attributed to an effective interaction of small-core vortices, which only exists over a short distance owing to linear diffraction. However, in a self-defocusing medium the vortices may propagate without diffraction (as solitons), and thus may exhibit enhanced rotation angles. An experimental confirmation of this enhancement is reported.