Controlling nonlinear wave structures in layered metamaterial, gyrotropic and active media

We use in this work, as one of the main methods, the new method of nonlinear evolution equations in layered structures (NEELS) for derivation of the nonlinear equations for amplitudes envelopes of wave packets in layered systems included nonlinear gyrotropic layers and surface. On the basis of this method, the new controllable wave structures in gyrotropic active layers with parametric coupling are investigated and the new “knife-type” of spatio-temporal (2+1) solitons/bullets in this gyrotropic layers are found. Formation and propagation of bullets in model metamaterial waveguide with magnetooptic control are investigated. Two types of nonlinear instabilities of bullets are revealed and the effects of higher-order nonlinearities (nonlinear dispersion and diffraction) on the bullet formation is investigated. A possibility of stabilization of bullets due to magnetooptic control is shown. An effect of “stabilization of amplification” of the bullets in a layered media with the diffraction management id found. Possible applications in optics, signal processing, and space communication are discussed

Strong nonlinear focusing of light in nonlinearly controlled electromagnetic active metamaterial field concentrators

The idea of nonlinear 'transformation optics-inspired' [1–6] electromagnetic cylindrical field concentrators has been taken up in a preliminary manner in a number of conference reports [7–9]. Such a concentrator includes both external linear region with a dielectric constant increased towards the centre and internal region with nonlinearity characterized by constant coefficients. Then, in the process of farther investigations we realized the following factors considered neither in [7–9] nor in the recent paper [10]: saturation of nonlinearity, nonlinear losses, linear gain, numerical convergence, when nonlinear effect becomes very strong and formation of 'hotspots' starts. It is clearly demonstrated here that such a strongly nonlinear process starts when the nonlinear amplitude of any incident beam(s) exceeds some 'threshold' value. Moreover, it is shown that the formation of hotspots may start as the result of any of the following processes: an increase of the input amplitude, increasing the linear amplification in the central nonlinear region, decreasing the nonlinear losses, a decrease in the saturation of the nonlinearity. Therefore, a tendency to a formation of 'hotspots' is a rather universal feature of the strongly nonlinear behaviour of the 'nonlinear resonator' system, while at the same time the system is not sensitive to the 'prehistory' of approaching nonlinear threshold intensity (amplitude). The new proposed method includes a full-wave nonlinear solution analysis (in the nonlinear region), a new form of complex geometric optics (in the linear inhomogeneous external cylinder), and new boundary conditions, matching both solutions. The observed nonlinear phenomena will have a positive impact upon socially and environmentally important devices of the future. Although a graded-index concentrator is used here, it is a direct outcome of transformation optics. Numerical evaluations show that for known materials these nonlinear effects could be readily achieved