Europhys. Lett.
Volume 72, Number 5, December 2005
Page(s) 698 - 704
Section General
Published online 26 October 2005
Europhys. Lett., 72 (5), pp. 698-704 (2005)
DOI: 10.1209/epl/i2005-10295-7

Higher-order vortex solitons, multipoles, and supervortices on a square optical lattice

H. Sakaguchi1 and B. A. Malomed2

1  Department of Applied Science for Electronics and Materials Interdisciplinary Graduate School of Engineering Sciences Kyushu University - Kasuga, Fukuoka 816-8580, Japan
2  Department of Interdisciplinary Studies School of Electrical Engineering, Faculty of Engineering Tel Aviv University - Tel Aviv 69978, Israel

received 4 April 2005; accepted in final form 29 September 2005
published online 26 October 2005

We predict new generic types of vorticity-carrying soliton complexes in a class of physical systems including an attractive Bose-Einstein condensate in a square optical lattice (OL) and photonic lattices in photorefractive media. The patterns include ring-shaped higher-order vortex solitons and supervortices. Stability diagrams for these patterns, based on direct simulations, are presented. The vortex ring solitons are stable if the phase difference $\Delta \phi $ between adjacent solitons in the ring is larger than $\pi /2$, while the supervortices are stable in the opposite case, $\Delta \phi <\pi /2$. A qualitative explanation to the stability is given.

03.75.Lm - Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations.
05.45.Yv - Solitons.
42.65.Tg - Optical solitons; nonlinear guided waves.

© EDP Sciences 2005