Elliptical light bullets

We address the existence and properties of three-dimensional solitons local ized in space and time, or light bullets, in bulk dispersive quadratic nonl inear media under conditions for Type I second-harmonic generation, with em phasis on the general case of different group-velocity dispersions at the f undamental and second-harmonic frequencies. We find families of three-dimen sional light bullets and study their features in detail, including their st ability on propagation. Most of the three-dimensional spatio-temporal solit ons are shown to be stable. (C) 1999 Elsevier Science B.V. All rights reser ved.