We demonstrate experimentally the generation of square and hexagonal lattices of optical vortices and reveal their propagation in a saturable nonlinear medium. If the topological charges of the vortices have identical signs, the lattice exhibits rotation, whereas if their signs alternate between being the same and being opposite to each other, we observe stable propagation of the structures. In the nonlinear medium the lattices induce periodic modulation of the refractive index. Diffraction of a probe beam by this nonlinearity-induced periodic structure is observed.
© 2002 Optical Society of America
Alexander Dreischuh, Sotir Chervenkov, Dragomir Neshev, Gerhard G. Paulus, and Herbert Walther, "Generation of lattice structures of optical vortices," J. Opt. Soc. Am. B 19, 550-556 (2002)