Tunable beam splitting via photorefractive nonlinearity and its applications in chiral waveguide induction and vortex generation

We report experimental observation and theoretical explanation of novel propagation regimes for optical beams in an artificial nonlinear material with outstanding photorefractive properties. Nondiffractive beams, which keep their shapes invariant in the free space, feature self-splitting from the middle in two separating secondary beams, due to the light-matter interaction. The splitting degree is controlled by means of a phase-pre-modulation method. We propose applications of the self-splitting to the creation of an effectively chiral waveguide and the generation of even-order vortices.