The most efficient optical phase conjugation in dynamic holographic systems

The four-wave mixing (FWM) technique for optical phase conjugation (OPC) has been acknowledged for a real-time OPC mirroring. Its main advantage lies in the adjustment of wavefronts via self-diffraction of interacting waves on the phase dynamic grating occurring in reversible optical nonlinear media. The feature of wave-mixing is to create a periodic modulation of the refractive index, the so-called photo-induced dynamic grating, by acting with an interference light field. In this paper, we derive the dynamical system of equations for the FWM as an equivalent system of coupled wave equations that describes the nonlinear interaction between two lattices: the governing light lattice and the driven dynamic material grating. Further we use a new approach: nonlinear processes of self-organization in this system are considered from the point of view of dissipative soliton (DiS) formation. Thus, we study the properties of DiS of dynamic lattice interaction (DiSLI), which may be regarded as a new kind of spatial dissipative soliton. DiSLI exhibits a spatially inhomogeneous longitudinal envelope for the intensity in the maxima of the light interference field so as leads to inducing spatial localization of the dynamic grating amplitude along the thickness of the medium z. The physical mechanism for the emergence of a spatially localized envelope for the interference intensity is the energy transfer effect that occurs between interacting waves at wave-mixing in a bulk nonlinear medium. We analyze the conditions when a strongly localized DiSLI is formed exactly within the nonlinear medium. In this case the effect of considerable energy transfer from pump waves to the signal wave is realized, accompanied by a significant increase in the gain for the OPC-wave. Furthermore, we reduce the description of initial nonlinear system to a single complex Ginzburg-Landau equation (CGLE), by employing the multiscale expansion method.