Dynamics of femtosecond laser filamentation in argon with non-uniform density distribution

We numerically investigated the femtosecond laser filamentation in a cell filled with argon of non-uniform density distribution. By comparison with the case of uniform density distribution, we demonstrated the crucial differences in the dynamics between the two cases. We found that the pulse-splitting appeared earlier due to the sensitivity of rear-part refocusing to the plasma density and a double Λ shape appeared in the spatio-temporal intensity profile in the non-uniform density case.