Nonlinear chirped soliton: self-formation at Gaussian pulse propagation in a medium with non-instantaneous nonlinear response

摘要

Non-instantaneous nonlinear medium response is a widespread case for a propagation of laser pulse with femtosecond duration. It occurs if a femtotosecond pulse propagates in fused silica or in air at sufficient high incident intensity, or in a medium, containing nanoparticles, for example. The last propagation case is very important for practical application at developing of all-optical multi-dimensional devices for data storage. As a rule, such femtosecond laser pulse propagation is accompanied by nonlinear non-stationary absorption. In the media with nonlinear non-stationary absorption a self-similar mode of a femtosecond pulse propagation is of great interest because of its spectrum unchanging at the distances up to several dispersion lengths at least. In our report we predict and investigate a novel type of solitons (or similariton) -nonlinear chirped solitons- formation if a nonlinear absorption and/or nonlinear refraction of the laser pulse occurs. This type of solitons is characterized by a nonlinear complicated frequency chirp and can possess an asymmetric pulse shape.