We report what is believed to be the first experimental observation of spontaneous nucleation of arrays of optical vortices in the process of second-harmonic generation in a crystal with moderate Poynting vector walk-off, pumped with focused beams containing screw phase dislocations. Our experiments were conducted in lithium triborate under conditions of small-efficiency second-harmonic generation pumped by nanosecond pulses at 1064 nm.
© 2002 Optical Society of America
Gabriel Molina-Terriza, Dmitri V. Petrov, Jaume Recolons, and Lluis Torner, "Observation of optical vortex streets in walking second-harmonic generation," Opt. Lett. 27, 625-627 (2002)