The nonlinear dynamics of a high-power femtosecond singular pulse in Kerr media are analyzed numerically upon optically induced ionization. We examine the plasma inertia impact to stable propagation of optical vortices. Multifoci behavior of vortices in medium are revealed. Next we numerically demonstrate that inertial character of plasma formation provides a quasi-soliton regime of vortex propagation resistant to symmetry-breaking perturbation.

No abstract

Methods of characterization of nanocomposites consisting of semiconductor quantum dots incorporated into a transparent nonlinear dielectric matrix are elaborated. Spectral composition, observation time, and phase-matching conditions for echo-responses excited by two noncollinear pulses are analysed. More specifically, spectral and spatial features of echo signals caused by permanent dipole moments (PDMs) inherent to quantum dots and local field effects in them, as well as by the angular distribution function of the PDM orientations and spatial dispersion of transition dipole moments, are considered.

Abstract. Nonlinear dynamics of high-intensity femtosecond singular pulses in a Kerr medium with group velocity dispersion (GVD) is analysed using variational and numerical approaches. We study underlying physical processes governing propagation of vortices: diffraction, Kerr self-focusing, defocusing due to photoinduced plasma, and normal/anomalous GVD. Multifoci behaviour of vortices appearing in the medium are revealed. It is shown that the refocusing period depends on both the magnitude and sign of the GVD. The early stages of vortex beam filamentation are described.

No abstract