Filamentation and coalescence of singular optical pulses in narrow-gap semiconductors and modeling of self-organization of vortex solitons using two-photon absorption

Short intense laser pulses with phase singularity propagating in narrow-gap semiconductors are modeled. The saturating nonlinearity is a prerequisite for self-organization of pulses into solitons. The cubic-quintic saturation appears due to the conduction-band nonparabolicity in synergy with the free carriers excitation through two-photon absorption. The pulse stability analyzed using Lyapunov’s method is confirmed by numerical simulations. Depending of its power, a singular Gaussian pulse far from equilibrium either filaments or subsequently coalesces evolving toward vortex soliton. Above breaking power, such a vortex soliton resists to azimuthal symmetry-breaking perturbations

Picosecond nonlinear optical features of ferroelectric A(6)M(2)M(8)O-30 large sized nanocrystallites

Second and third order nonlinear optical susceptibilities of A(6)M(2)M(8)O-30 ferroelectric crystallites 100 nm powders were studied. The measurements were carried out for powders and thin films of guest-host composites made of Poly(methyl methacrylate) (PMMA) matrix. The studies were carried out by Kurtz Perry method using a Q-switch 16 ps picosecond Nd:YAG laser with peak pulse power 25 MW operating at 1064 nm fundamental wavelength. We have established that Ba6Ti2Nb8O30 ferroelectric crystallites achieve the highest (among the studied materials) second order optical susceptibilities equal to about 8.12 pm/V. The use of picosecond laser pulses and of the crystallites with high monodispersion allow to obtain an information concerning the second order optical susceptibilities with the avoiding of the local thermoheating which may change the output susceptibilities

Finding Solitons in Bifurcations of Stationary Solutions of Complex Ginzburg-Landau Equation

Nonlinear dissipative systems, particularly optical dissipative solitons are well described by complex Ginzburg-Landau equation. Solutions of two- and three-dimensional complex cubic-quintic Ginzburg-Landau equation assuming exponential dependence on propagation parameter are studied. Approximate analytical stationary solutions of cubic-quintic Ginzburg-Landau equation are found by solving systems of ordinary differential equations. We are solving two-point boundary problems using adapted shooting method. Stable and unstable branches of the bifurcation diagram are identified using linear stability analysis. In this way we established conditions for generation and propagation of stable dissipative solitons in two and three dimensions. These results are in agreement with numerical simulation of cubic-quintic Ginzburg-Landau equation and the recently established approach based on variational method generalized to dissipative systems and therein established stability criterion