Search

Abstract. We review the generation of the recently predicted multi-component spatial optical solitons in a saturable nonlinear bulk medium. We present numerical simulations for an effectively isotropic model and experimental results for a set of different combinations of a Gaussian beam co-propagating incoherently with a beam of a more complex internal structure, such as a higher order transverse laser mode. We discuss the different formation processes and the general properties of a variety of different dipole-mode composite solitons and expand our investigations to the generation of a quadrupole-mode composite soliton. [ABSTRACT FROM AUTHOR]

Abstract. We present a review of our recent theoretical and experimental results on the interaction of incoherent twodimensional solitary beams in PR SBN crystals. We show that the inherent anisotropy of PR nonlinearity strongly affects the interaction between solitons. Theoretical and experimental results reveal that solitons interacting in a plane perpendicular to the direction of external biasing field always attract, whereas those colliding in a plane of the field exhibit anomalous behaviour. They may experience both attractive and repulsive forces, depending on their mutual separation. We also show that this anisotropy results in the complicated topology of soliton trajectories, featuring periodic collisions, prolonged mutual spiraling and collapse, depending on the initial conditions. [ABSTRACT FROM AUTHOR]

We study here the four-wave mixing in photorefractive crystals with light beams of partial temporal coherence. We consider the evolution of the mutual coherence of the beams due to interaction and show how the partial coherence affects the efficiency of the phase conjugation process. In particular, we demonstrate that while initial low mutual coherence may be improved by wave mixing, it usually leads to a significant drop of the phase conjugate reflectivity. [ABSTRACT FROM AUTHOR]

The effect of high contrast in photorefractive four-wave mixing is studied using a recently proposed empirical formula for the grating amplitude. An analytical solution to the coupled-wave equation is obtained and its properties are discussed in the case of a double-phase-conjugate mirror and semilinear phase-conjugate mirror. [ABSTRACT FROM AUTHOR]