Suppression of Anderson localization of light and Brewster anomalies in disordered superlattices containing a dispersive metamaterial

Abstract

Light propagation through one-dimensional disordered structures composed of alternating layers, with random thicknesses, of air and a dispersive metamaterial is theoretically investigated. We have established that Anderson localization of light may be suppressed: (i) in the long-wavelength limit, for a finite angle of incidence which depends on the parameters of the dispersive metamaterial; (ii) for isolated frequencies and for specific angles of incidence, corresponding to Brewster anomalies in both positive- and negative-refraction regimes of the dispersive metamaterial. On the other hand, in the long-wavelength limit, the localization length tends to a constant value for sufficiently large angles of incidence, in contrast to what is generally expected for disordered systems. We also find that delocalization at the very edge of a band gap is possible, a result which could be explored to observe slow light propagation in disordered photonic structures.