V. V. Ivakhnik

Phase conjugation under four-wave mixing on resonant and thermal nonlinearities at relatively high reflection coefficients

The dependences of the reflection (transmission) coefficients and the half-width of the spatial frequency band on the pump-wave intensity are obtained for an object (signal) wave in degenerate and quasi-degenerate four-wave mixers on resonant and thermal nonlinearities. The effect of the difference of the pump-wave frequencies on the phase-conjugation quality is studied at relatively high reflection coefficients.

Diffraction efficiency of a dynamic hologram in a reversible photochromic medium with allowance for diffusion of photochromic particles

Spatial resolution of a dynamic hologram in a reversible photochromic medium is analyzed, with allowance made for diffusion of photochromic particles. It is shown that the bandwidth of spatial frequencies of a thin hologram decreases over time, approaching the value determined by the diffusion coefficient and the hologram recording/erasing time. The optimum relationship between the intensity of the beam that records the volume hologram and the parameters of the photochromic particles is found for which the difference between the limiting value of the bandwidth of spatial frequencies of the volume hologram and the value of the band-width of spatial frequencies of a thin hologram located in the plane z=0 is the greatest.

Degenerate four-wave mixing in transparent two-component medium considering spatial structure of the pump waves

In this paper we investigate spatial selectivity of the degenerate four-wave radiation converter in transparent liquid containing nanoparticles considering spatial structure of the pump waves. The bandwidth of the most efficiently converted spatial frequencies is associated with the rotation and divergence of the pump waves.

Precision of wavefront reversal during four-photon interaction of nonmonochromatic waves

The form of the point spread function is found for a stabilized four-photon radiation converter. The functional dependence of the maximum, half-width, and phase shift at the point spread function modulus half-width on the frequency shift of the interacting waves is investigated when the focal planes of the incident and reflected waves coincide. The dependence of the resolution of a four-photon radiation converter as a function of the spectral width of the interacting waves was analyzed with the monochromaticity of these waves taken into account. The effect of the rate of change of the linear phase difference between the different components of the reflected wave on the coherent component of the point spread function was studied.

Phase-conjugation quality with four-photon interaction in a parabolic waveguide

The effect of the mode structure of the pump waves and the length of the optical waveguide on phase conjugation quality with degenerate four-photon interaction in a parabolic optical waveguide with Kerr nonlinearity is studied. It is shown that the dependence of the overlap integral on the mode numbers of the interacting waves eliminates the possibility of ideal phase conjugation in “long” optical waveguides. As the length of the waveguide increases, the point-spread function, describing the quality of phase conjugation, is broadened and approaches some limiting form, determined by the mode structure of the pump waves. In “long” waveguides, if one of the pump waves is single-mode and the other is multimode, an increase in the mode numbers of multimode pumping affects only the contrast and symmetry of the converted image of a point. If, however, both pump waves are identical and multimode, then an increase of their mode number results in narrowing of the point-spread function.

Optical radiation filtration with nondegenerate four-photon interaction

The effects of frequency shift between incident and reflected waves, conversion efficiency, and positive feedback coefficient on quality of wave-front rotation are studied for nondegenerate four-photon interaction.