A. S. Rubanov

Contribution of resonance medium amplitude and phase modulation to the effectiveness of phase conjugation by degenerate four-wave mixing

The contribution of amplitude and phase modulation to the energetic efficiency of wavefront conjugation (WFC) under degenerate four-wave mixing is studied in resonant media simulated by a two- or a three-level scheme. It is shown that a WFC-mirror of reflectivityR higher than unity may be achieved only in the presence of the medium phase modulation. Optimum conditions for obtaining high-efficiency (R>1) WFC are defined.

Acoustic Response of Multilayer Biostructures to Laser Irradiation and the Possibility of Using It in Surgery and Diagnostics

Aspects of the destructive action of short laser pulses on multilayer biological structures are considered theoretically. The proposed mechanisms of destruction of the native structure are cavitation, explosive evaporation, and thermocoagulation. The parameters (power and duration) of laser radiation pulses (λ = 534 nm‐, controlling which one can choose the character of the destructive (from mechanical to pure thermal) action on the skin, have been calculated. The possibility of early diagnostics of pigmented tumors by the parameters of the hydroacoustic response of the medium is shown.

Optical multistability from four-wave mixing in a resonant medium

Abstract A theoretical study is made of the conditions for bifurcation and optical multistability at degenerate FWM in a resonant medium taking into account nonlinear absorption and energy pumping between all interacting waves.

Double phase conjugation by nondegenerate four-wave mixing

The possibility of phase conjugation with simultaneous doubling of the light-wave phase and frequency upon nondegenerate four-wave mixing has been suggested and substantiated theoretically. The dependence of the energy efficiency of double-phase conjugation on the spectroscopic characteristics of the multilevel resonant media has been analyzed.

Image reconstruction by volume holograms with frequency conversion

The schemes of the coherent-image frequency conversion based on transmission and reflection dynamic gratings are studied. The effect of the processes of recording-waves energy exchange and absorption in a medium volume upon the diffraction efficiency of a reconstructing beam is investigated within the scope of a theory of four-wave mixing. Comparison with the case of degenerate four-wave mixing has been conducted and the possibility of the diffraction- efficiency improvement under the frequency shift of a reconstructing beam beyond the absorption band has been analyzed.

Four-wave mixing in multilevel media at spatially homogenous irradiation

Theoretical analysis of nonconventional schemes of four-wave mixing (FWM) using additional irradiation of resonance medium, which enables the realization of noncoherent optical control of the process efficiency, has been carried out. The possibility of significant increase in the phase conjugate reflectivity and decrease in the pump wave intensity, required for realization of optical bistability, has been shown. Optical control and intensification of FWM in Rhodamine 6G solution have been experimentally accomplished

Four‐Wave Mixing in a Nonlinear Fabry–Perot Interferometer

A theoretical model of four‐wave mixing in a Fabry–Perot interferometer with resonant nonlinearity has been developed. The conditions for the realization of the effect of interferometer transmission symmetry breaking and the specific features of the formation of space‐time structures of light fields have been analyzed. The laws of hysteresis of the lateral laser beam profiles have been established.

Spatial and temporal structures of light fields in nonlinear interferometer

Investigation of nonlinear interferometers symmetrically pumped by two light beams has been proposed. An analysis of the conditions for realization of symmetrical and asymmetrical optical bistability, different spatial-temporal structures due to symmetry breaking bifurcation has been performed.

Transition to chaos in an interferometer with amplitude-phase nonlinearity

A theoretical investigation into the dynamics of Fabry-Perot interferometer (FPI) with multilevel resonant medium has been conducted. The origin conditions and characteristics of complex dynamic operating modes of FPI have been analyzed at constant intensity of the input light beam. The mechanisms of switching from regular intensity oscillations to the chaotic ones through the sequence of period-doubling bifurcations or multiple pass Shilnikovs attractor have been demonstrated.

Complex dynamic operation modes of an interferometer with resonance nonlinearity

The possibility of generation in a nonlinear interferometer of the complex-form intensity pulsations through the concurrent resonance nonlinearities due to transitions of molecules to different energy states has been put forward and substantiated. The conditions and character of transition to the mode of dynamic chaos have been analyzed.