Self-similar chirped laser pulse propagation in a medium with TOD and non-resonant TPA

Abstract

We study a self-similar mode of femtosecond pulse propagation in a medium with non-resonant TPA of laser energy and with taking into account the TOD influence. Non-resonant TPA appears due to detuning between a carrier frequency of wave packet and doubled frequency corresponding to certain energy level transition of substance atoms. This pulse propagation mode appears for a pulse with nonlinear chirp of definite form. Moreover, the pulse shape is asymmetric, as a rule. Laser pulse propagation in nonlinear medium is described by nonlinear Schrodinger equation. Using the analytical approach we derive a soliton-like pulse shape and its chirp evolution in time. Analytical results are confirmed by computer simulation, based on nonlinear Schrodinger equation. We demonstrate that the analytical results are valid at a long propagation distance.