The combined effects of diffraction and Poynting vector walk-off in second-harmonic generation with pump beams that contain screw phase dislocations is addressed for what is believed to be the first time. We predict the spontaneous nucleation of multiple vortex twins whose subsequent explosion can yield quasi-aligned patterns of single-charge vortices.
© 1999 Optical Society of America
(050.1940) Diffraction and gratings : Diffraction
(140.3300) Lasers and laser optics : Laser beam shaping
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.7070) Nonlinear optics : Two-wave mixing
Gabriel Molina-Terriza, Lluis Torner, and Dmitri V. Petrov, "Vortex streets in walking parametric wave mixing," Opt. Lett. 24, 899-901 (1999)