V. E. Lobanov

Optical pulse velocity and frequency variations during cascade parametric interaction with a high powered reference pulse

The effect of a frequency shift and time delay during the cascade parametric interaction of a weak signal pulse with a high powered reference pulse is demonstrated for the first time. The conditions of total reflection of a pulse signal in a crystal with quadratic nonlinearity are found. The equation for the frequency shift of a reflected wave is derived.

Diffraction of optical waves by nonlinearly induced cylinders

The diffraction of optical waves by transparent and opaque cylinders formed by laser beams in defocusing nonlinear media has been investigated for the first time. The wave flow around a single beam (cylinder) and wave signal percolation through the slits formed by closely spaced laser beams have been numerically modeled.

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.

Cascaded induced lattices in quadratic nonlinear medium

We first study features of optical periodic lattices generated with mismatched cascade three-wave interaction in quadratically nonlinear media. We elaborate the theory of parametric waveguides arrays induced by two crossing pump waves together with exited sum wave. As the signal wave spreads due to the diffraction the induced lattice appears and its transverse dimension increases. Note the parametric periodic grating becomes apparent since launching any signal beam. Its likely to be the leading peculiarity of cascaded induced lattices. Parametric inhomogeneity depends on wave vector mismatch sign, and its modulation depth can be controlled by pump beam intensity. We observed a transformation from the discrete diffraction into the waveguiding of one or several signal beams with the increasing of pump intensity. The discrete diffraction dynamics dependence on pump intensity, spatial period, and signal beam tilting is analyzed when one or few central waveguides are exited at the input. At the certain incidence diffractionless propagation of signal beam takes place. The similar discrete diffraction effects in 2D cascaded lattices with various pump structure geometries have been studied. The additional degree of freedom gives novel properties to the effect of discrete diffraction.

Discrete diffraction and waveguiding of optical beams in a cascade-induced lattice

Regularities of anisotropic discrete diffraction in a cascade-induced lattice formed by two crossed pump waves in a quadratically nonlinear medium have been studied. The transition from diffraction of a signal beam in free space to discrete diffraction with further capture into a waveguide in a defocusing lattice with an increase in the pump wave intensity has been traced. Diffraction-free propagation of a tilted beam is described.

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.

Collision of optical pulses in nonlinear dispersive media: frequency tuning and velocity variation

The total reflection effect of the weak signal pulse from the high-power reference pulse with another frequency is first demonstrated in the dispersive nonlinear medium. It is shown that as a result of the binary collision, signal pulse frequency shift occurs, propagation velocity changes and time delay takes place. The conditions of total internal reflection from moving inhomogeneity induced by pump pulse in nonlinear medium are found. The expression for the reflected wave frequency shift is obtained. The possibility of pulse reflection from bright solitons in cubic medium is considered.

Fundamental Limits for Compression Dynamics of Few‐Cycle Pulses

A theory of compression of a few‐cycle pulse with quadratic phase modulation has been developed within the SVP method. The equation for the electric field was numerically solved varying the phase modulation index, number of oscillations, and input pulse width. The optimal modulation index was found, at which a pulse can be compressed to one oscillation period. When the modulation index exceeds the optimal value, the width at the compression point increases.

Propagation and interaction of ultra-short pulses in quadratic crystals with controlled dispersion

Propagation of ultra-short optical pulses in an environment with quadratic nonlinearity and modulated dispersion is studied. It is shown that periodic modulation of the velocity-mismatch sign and of the third-order dispersion coefficient allows one to suppress pulse scattering and decompression, which noticeably increases their interaction efficiency.

The propagation of wave beams in 2D cascade-induced lattices

A new method of 2D periodic lattices excitation in quadratically nonlinear media with cascade interaction is suggested. It is shown that in such structures the all-optical management of laser beams could be carried out. The possibility of switching waveguides and changing the final energy distribution among channels using the phenomenon of discrete diffraction is demonstrated.