SPATIOTEMPORAL SOLITON PROPAGATION IN SATURATING NONLINEAR-OPTICAL MEDIA

The simultaneous balance of nonlinear spatial self-focusing with diffr action and the compensation of dispersion with nonlinear temporal self -focusing, in a saturating nonlinear medium, give stable spatiotempora l solitons, or ''light bullets.'' An analytical approach for arbitrary saturating nonlinearity is established in order to investigate the dy namics of such light bullets. This approach is applied to nonlinear ma terials with negative fourth-order optical index. The analytically pre dicted exceptional robustness of light bullets that can be generated i n a large range of parameters is confirmed by numerical simulations.