Control of Transversal Interactions in Nonlinear Optics: New Spatio-Temporal Effects in Nonlinear Wave Dynamics

Abstract

Control of the topology and the scale of transverse interactions leads to a new class of spatio-temporal light beam instabilities in media with cubic nonlinearity.

In this paper we present the results of theoretical and experimental investigations of instabilities and spatio temporal nonlinear wave structures which are driven by large scale coherent transverse interactions.

In Refs. 1 and 2 we have suggested and implemented some arrangements with so-called two-dimensional (2D) feedback, in which the characteristic scale of transverse interactions L_⊥ ~ d, where d is the beam width. Depending on the parameter values of the nonlinear medium and the initial boundary conditions, a complete nonlinear wave dynamics hierarchy including steady-state dissipative structures, rotating waves (optical reverberators), spiral waves, and optical turbulence can be observed. With optical reverberators we observed the new effect of light field nonlinear dynamics — the hysteresis of rotating nonlinear structures (see also Ref. 3). The theory, based on the nonlinear parabolic equation with a shifted spatial argument, explains the experimental data quantitatively. Some very new experimental results on spatially nonlinear structures, locked by the external light, are also presented. Optical turbulence scenarios in systems with 2D feedback are discussed in comparison with ID dynamical optical chaos. Among the applications of the considered phenomena the generation of classical spatial squeezed states and optical modeling of neural networks will be mentioned (Ref. 4).