Spinning light bullets

Summary form only given. Optical spatio-temporal solitons, or light bullets (LB), are fundamental physical objects with a potential for applications in ultrafast all-optical switching. They result from a balance of diffraction, anomalous dispersion and self-phase modulation. In dispersive media with a self-focusing cubic nonlinearity they are subject to collapse. This collapse can be arrested in saturable cubic as well as in quadratic nonlinearities. In the latter environment LBs have been experimentally observed in an LiIO/sub 3/ optical crystal. We identify one-parameter families of 3D spinning LBs in media with either a quadratic or a cubic-quintic nonlinear medium, where the latter is typical for a PTS crystal and study their dynamics. In the quadratic scenario our model assumes different coefficients of the group velocity dispersion (GVD) for the two different frequencies but neglects walk-off and temporal group-velocity mismatch. A crucial issue is the stability of the spinning LBs against azimuthal perturbations which are considered for the first time.