Yu. S. Kivshar

Dynamics of coupled dark and bright optical solitons.

We theoretically examine the interaction between two solitons in a double-mode optical fiber. The bound state between two solitons of different modes is investigated, including both dark and bright solitons. It is shown that interaction between dark solitons as well as between bright solitons is always attractive, but the interaction between bright and dark solitons may be repulsive. Analytical results are in agreement with numerical ones.

Bright and dark spatial solitons in non-Kerr media

An overview of the theory of self-guided optical beams, spatial optical solitons supported by non-Kerr non-linearities, is presented. This includes bright and dark solitons in optical media with intensity-dependent non-linear response as well as two-component solitary waves supported by parametric wave mixing in quadratic or cubic media. The properties of non-linear spatially localized waves are discussed for qualitatively different types of soliton bearing non-integrable non-linear models, including the scalar model described by a generalized non-linear Schrödinger equation and the models of the second- and third-harmonic generation. Special attention is paid to the recent advances of the theory of soliton stability and soliton internal modes.

Nonlinear metal-dielectric nanoantennas for light switching and routing

We introduce a novel hybrid metal?dielectric nanoantenna composed of dielectric (crystalline silicon) and metal (silver) nanoparticles. In such a nanoantenna, the phase shift between the dipole moments of the nanoparticles, caused by differences in the polarizabilities, allows for directional light scattering; while the nonlinearity of the metal nanoparticle helps to control the radiation direction. We show that the radiation pattern of this nanoantenna can be switched between the forward and backward directions by varying only the light intensity around the level of 6?MW?cm?2, with a characteristic switching time of 40?fs.

Fano resonances and topological optics: an interplay of far- and near-field interference phenomena*

Fano resonances and optical vortices originate from two types of interference phenomena. Usually, these effects are considered to be completely independent, and in many cases Fano resonances are observed without any link to vortices, as well as vortices with a singular phase structure that are not accompanied by Fano resonances. However, this situation changes dramatically when we study light scattering at the nanoscale. In this paper, we demonstrate that Fano resonances observed for light scattering by nanoparticles are accompanied by the singular phase effects usually associated with singular optics, and we introduce and describe optical vortices with characteristic core sizes well below the diffraction limit.

Dynamics of solitons under random perturbations

Abstract The dynamics of solitons is investigated in media with randomly inhomogeneous and fluctuating parameters. Some exact results of the theory of nonlinear stochastic waves are given. An analysis is made of various approximate approaches, e.g. of the mean field method and the Born approximation. Special attention is paid to the perturbation technique based on the inverse scattering transform and to the construction of the most adequate stochastic perturbation theory for solitons. The described formalism is used to investigate the evolution of nonlinear wave (soliton) parameters, and the statistical characteristics of radiation generated by solitons in fluctuating media are analysed also. The same approach makes it possible to take into account the simultaneous effect of random and regular (e.g., friction) perturbations on the dynamics of solitons. Examples are given of situations arising when one describes nonlinear waves in real physical systems.

SCATTERING AND SPIRALING OF SOLITONS IN A BULK QUADRATIC MEDIUM

We analyze the interactions of (2+1) -dimensional parametric solitons and demonstrate nonplanar beam switching in a bulk X((2)) medium, which includes controllable soliton repulsion, spiraling, and fusion. An analytical model predicting the results of the soliton scattering is derived and verified by direct numerics.

Nonlinear interaction of meta-atoms through optical coupling

We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.

All-optical switching of a signal by a pair of interacting nematicons

We investigate a power tunable junction formed by two interacting spatial solitons self-trapped in nematic liquid crystals. By launching a counter-propagating copolarized probe we assess the guided-wave behavior induced by the solitons and demonstrate a novel all-optical switch. Varying soliton power the probe gets trapped into one or two or three guided-waves by the soliton-induced index perturbation, an effect supported by the nonlocal nonlinearity.

Dark solitons produced by phase steps in nonlinear optical fibers

Abstract We demonstrate analytically that dark solitons may be produced from phase steps in nonlinear optical fibers at the positive group velocity dispersion. We study the cases of a step and two steps in the phase of a cw background in detail. The parameters of general solitons are calculated. The influence of the background broadening and dissipative losses on the dark-pulse evolution is discussed too.

Propagation of nonlinear incoherent pulses in single-mode optical fibers

Abstract Propagation of incoherent nonlinear picosecond pulses in a single-mode optical fiber is considered within the framework of the nonlinear Schrodinger equation. Statistical characteristics of a non-soliton wave packet induced by a random input pulse are obtained with the help of the inverse scattering technique. The probability of a soliton creation from the random pulse is found. Mean soliton amplitude and velocity changings caused by small fluctuations of the soliton-like input pulse are calculated. The influence of dissipative losses on the obtained results is discussed.