Self pumped phase conjugation of angular momentum carrying light beams

Light beams with screw phase dislocations are known to carry optical angular momentum. A wide area of applications for this kind of beams are optical tweezers where angular momentum is transferred to microscopic samples e.g. in order to drive micro machines. In this contribution we investigate the properties of vortex beams reflected by a phase-conjugating mirror. It is shown that a self-pumped photorefractive phase-conjugating mirror is suitable to produce very stable, high-fidelity phase conjugation of vortex beams. We prove that the topological charge of the vortex beam is maintained, and thus the angular momentum in the laboratory frame of reference is reversed, as it is expected by the time reversal property of the phase-conjugating mirror.