Counterpropagating dipole-mode vector soliton

We experimentally observe a counterpropagating dipole-mode vector soliton in a photorefractive SBN:60Ce crystal. We investigate the transient formation dynamics and show that the formation process differs significantly from the copropagating geometry. The experimental results are compared with fully anisotropic numerical simulations which show good qualitative agreement.Comment: 4 pages, 4 figure

Incoherent multi-gap optical solitons in nonlinear photonic lattices

We demonstrate numerically that partially incoherent light can be trapped in the spectral band gaps of a photonic lattice, creating partially incoherent multi-component spatial optical solitons in a self-defocusing nonlinear periodic medium. We find numerically such incoherent multi-gap optical solitons and discuss how to generate them in experiment by interfering incoherent light beams at the input of a nonlinear periodic medium.Comment: 9 pages, 5 figure

Soliton transverse instabilities in anisotropic nonlocal self-focusing media

We study, both theoretically and experimentally, the transverse modulational instability of spatial stripe solitons in anisotropic nonlocal photorefractive media. We demonstrate that the instability scenarios depend strongly on the stripe orientation, but the anisotropy-induced features are largely suppressed for spatial solitons created by self-trapping of partially incoherent light.Comment: 3 pages including 4 figures (2 theoretical and 2 experimental). submitted to Optics Letter

Incoherent vector vortex-mode solitons in self-focusing nonlinear media

We suggest a novel type of composite spatial optical soliton created by a coherent vortex beam guiding a partially incoherent light beam in a self-focusing nonlinear medium. We show that the incoherence of the guided mode may enhance, rather than suppress, the vortex azimuthal instability, and also demonstrate strong destabilization of dipole-mode solitons by partially incoherent light

Incoherent interaction of nematicons in bias-free liquid-crystal cells

We study experimentally the propagation dynamics and interaction of a pair of mutually incoherent nematicons: spatial optical solitons in nematic liquid crystals. In contrast to earlier studies, we consider a bias-free liquid-crystal cell and compare the soliton interaction in copropagating and counterpropagating geometries. We analyze the dependence of nematicon interaction on input power and observe a direct manifestation of a long-range nonlocal nonlinearity. Attraction of counterpropagating solitons requires higher powers and longer relaxation times than that of copropagating nematicons due to losses-induced power asymmetry of counterpropagating nematicons.Comment: 5 pages, z figure

Counterpropagating beams in biased photorefractive crystals: anisotropic theory

We formulate an anisotropic nonlocal theory of the space charge field induced by the coherent counterpropagating beams in biased photorefractive crystals. We establish that the competition between the drift and diffusion terms has to be taken into account when the crystal cˆ axis is tilted with respect to the propagation direction of the beams. We demonstrate that this configuration combines the features of both spatial soliton formation without energy exchange and two-wave mixing with energy exchange leading to pattern formation