WALKING SOLITONS IN QUADRATIC NONLINEAR MEDIA

We study self-action of light in parametric wave interactions in nonli near quadratic media. We show the existence of stationary solitons in the presence of Poynting vector beam walk-off or different group veloc ities between the waves. We discover that the new solitons constitute a two-parameter family, and they exist for different wave intensities and transverse velocities. We discuss the properties of the walking so litons and their experimental implications.