title: Observation of quadratic optical vortex solitons
abstract: We report on the generation of stable dark-vortex solitons in large-phase-mismatched second-harmonic generation of self-defocusing type, sustained by a combined effect of transverse walk-off and finite beam size.
authors.affiliation: INFM and Department of Chemical, Physical and Mathematical Sciences, University of Insubria at Como, 22100 Como, Italy.
authors.lastname: Di Trapani P
authors.initials: W
authors.lastname: Chinaglia
authors.initials: S
authors.lastname: Minardi
authors.initials: A
authors.lastname: Piskarskas
authors.initials: G
authors.lastname: Valiulis