Dynamics of femtosecond filamentation with higher-order Kerr response

Abstract

The spatiotemporal dynamics of femtosecond filamentation is investigated by using an expanded nonlinear model, which includes the higher-order Kerr nonlinear response and nonlinear losses. The existence of the physical picture of optical turbulence due to the modulational instability of the nonlinear response is clearly displayed. This turbulent region is comparable with the observed “optically turbulent light guide” of “dynamic spatial replenishment” [Phys. Rev. Lett. 83, 2939 (1999)] in which the generation of plasma is dominative in the long-range filament formation. It indicates that the Kerr nonlinear response plays a dual role, rather than a retroactive effect that may lead to the collapse of the beam, in sustaining the propagation of filamentation of a powerful femtosecond laser pulse in the bulk of transparent media.