Vortex solitons and charge flipping in nematic liquid crystals

Here we report on experimental generation of single-charged vortex solitons in planar unbiased nematic liquid crystal cell. Experimentally observed dynamics of vortex profile is illustrated in numerical simulations. At low input power the initial radially symmetric vortex undergoes drastic transformation, with vortex "doughnut" breaking up into two fundamental beams with a dark core transformed into a tilted stripe, similar to vortex astigmatic transformations.