The spatial and temporal evolution of the broadband chirped pulse with small-scale self-focusing

Abstract

In this paper, the spatial and temporal evolutions of the broadband chirped pulse with small-scale self-focusing (SSSF) in nonlinear medium have been investigated by experiments and simulations. Firstly, we studied the spatial modulation growth of broadband pulse by experiment in CS 2 and the laser will produce many small peaks from perturbation modulation. It is found that modulation growth of chirped optical pulses is delayed with the pulse chirp increasing. And then we investigate the temporal evolution of the pulse at the modulation peak and bottom during the SSSF by numerical simulation. The simulation results indicate that pulse width at modulation peak is decreasing with the increasing of modulation peak intensity. But the pulse at modulation peak will broaden when the peak intensity reaches the maximum and then the pulse began to splitting into two parts. However, the pulse width at modulation bottom always broadens and finally reaches to a constant value. The simulation results are in agreement with the experimental results.