A. A. Kalinovich

The effect of total internal reflection of wave beams in nonlinear media

The recent papers that consider new effects attributed to the total refection of a weak beam at a more powerful beam with another frequency in nonlinear media are reviewed. As an example, the dynamics of the beam reflection in media with thermal nonlinearity and photorefractive crystals are analyzed.

Propagation of a Self-Similar Pulse in a Medium with One-Photon Transient Absorption

The shape of an optical self-similar pulse that propagates in a medium of finite length with noninstantaneous nonlinear absorption is found analytically. The pulse has an asymmetric shape and, in addition, frequency modulation, which confirms that it belongs to a new type of self-similar propagation modes of laser radiation—chirped pulses with a self-similar shape. The existence of pulses of this kind is also confirmed by results of computer simulation.

Spatial-temporal pulses in a waveguide under conditions of second harmonic generation

We study different regimes of spatial-temporal pulses propagation in a waveguide under conditions of second harmonic generation. In comparison with a homogeneous medium the waveguide geometry allows us to increase the number of input parameter sets for which light bullets can be observed. We demonstrate that provided defocusing nonlinearity combined with a focusing waveguide the formation of spatial-temporal solitons is possible due to the waveguide geometry only. Stable propagation of two-component light bullets at normal dispersion is confirmed numerically.

Formation of chirped solitons when a femtosecond pulse passes through a layer with an inhomogeneous refractive index in a medium with cubic nonlinearity

A way of forming a new class of solitons—chirped (or aberrational) solitons—when a pulse passes through a layered nonlinear structure in a cubically nonlinear medium is demonstrated by means of computer simulation. It is shown that the pulse frequency modulation of the resulting solitons is nonlinear.

Three-dimensional light bullets in anisotropic microdispersive media

Three-dimensional light bullets in Kerr media are known to be unstable. Different schemes were proposed to overcome this obstacle. One of them is to use a nonlinear parametric interaction. Such a type of interaction can be achieved in anisotropic micro-dispersive media where space dispersion is of importance. These media allow us to reach a simultaneous approximate fulfillment of group and phase matching. To study the general (3+1)D case we apply both an approximate analytical approach and numerical simulations. We suggest that nonlinear refraction manifests itself earlier than diffraction and dispersion. Both the general (3+1)D case and axial-symmetry case are studied. With the help of averaged Lagrangian method analytical solutions are derived provided that the fixed relation between the negative coefficients of the group velocity dispersion on both harmonics holds. We demonstrate that a spatiotemporal light bullet propagates for at least 300 nonlinear lengths in anisotropic media at second harmonic generation.

New mechanism of solitons formation at diffraction on a periodic inhomogeneity induced in a cubic nonlinear medium

Formation of solitons during the propagation of the initial Gaussian pulse in a Kerr medium and its diffraction on the induced periodic layer structure are described using the computer simulation. Dependence of the characteristics and the number of the resulting solitons on the parameters of the structure is demonstrated.

Interaction of pulsed laser beams in quadratic nonlinear media

A theory of three-wave cascade interaction of pulsed laser beams in quadratic nonlinear media is developed with regard to diffraction and dispersion. The space-time trajectories of signal motion in a medium with an inhomogeneity induced by high-power low-frequency pumping are analyzed. It is shown that total signal reflection from a moving localized inhomogeneity can be implemented. This reflection is accompanied by a change in the frequency, velocity, and propagation direction of the signal wave.

Optical vortices of parametrically coupled waves

We demonstrate two-component generation of one or three dislocations by equally charged input vortices, and two or four ones by oppositely charged singularities. The vortex 3D trajectories are calculated when the beams interact due to frequency conversion.