Propagation dynamics of femtosecond laser pulses in hollow fiber filled with argon

Abstract

The dynamics of femtosecond laser pulses propagating in a hollow waveguide filled with argon was investigated using a simulation model based on the 3D nonlinear Schroedinger equation (NLSE). The results show that if the intensity is low and no ionization takes places, the spatial profile of the beam does not change such that its propagation model may be reduced to simply a 1D model. On the other hand, if the intensity is high and in the presence of ionization, the spatial dynamics as well as temporal dynamics of the propagation become very complicated. By further elaborating the propagation dynamics, it was found that the self-focusing and plasma defocusing are the origin of the complicated structure of the spatio-temporal intensity profiles.