Multiple-cone formation during the femtosecond-laser pulse propagation in silica

Summary form only given. In this study, by 3D numerical simulations with axial symmetry, we show that the propagation of a pulse with a power several hundreds of times higher than P/sub cr/ in silica is qualitatively different from lower-power cases. The pulse is split both temporally and spatially to form multiple cones. We model the pulse propagation with the extended nonlinear Schrodinger equation including the normal and third-order group velocity dispersion, transverse diffraction, the Kerr nonlinearity, plasma defocusing, multi-photon absorption, space-time focusing, and self-steepening.