Anomalous transmission in waveguides with correlated disorder

We have analyzed the influence of long-range correlations on transport properties of 1D and quasi-1D disordered systems from the unified viewpoint. For 1D structures, specific correlations in random potentials are known to result in an appearance of the mobility edges. This prediction is already confirmed experimentally for one-mode waveguides with delta-like scatters. The same effect is also expected for the surface scattering in the waveguides provided only one channel of propagation is open. On the way to a more general problem of the correlated disorder in quasi-one dimensional structures, we have studied a simplified quasi-1D model with a stratified disorder. This model absorbs both the properties of 1D correlated structures, and those that are specific for quasi-1D models with the surface scattering. The peculiarity of this model is that on the one hand, the transport in any of the channels is independent from the others. On the other hand, since the localization length in each channel strongly depends on its number, the total transmittance can not be expressed in terms of the theory of 1D localization. As a result, the effects of long-range correlations turn out to be highly non-trivial, leading to quite unexpected conclusions. In particular, it was shown that with a proper choice of the binary correlator describing correlation properties of the random potentials, one can arrange the situation when some of the channels are completely transparent and the others are closed. This interplay between localized and transparent channels can be controlled by specific long-range correlations. As a result, one can observe new effects of propagation of electron or electromagnetic waves in such quasi-1D structures. Our study may find practical applications for fabrication of electromagnetic/acoustic waveguides, optic fibers and electron nanoconductors with a selective transport.