Localization in Correlated Bi-Layer Structures: From Photonic Cristals   to Metamaterials and Electron Superlattices
  In a unified approach, we study the transport properties of periodic-on-average bi-layered photonic crystals, metamaterials and electron superlattices. Our consideration is based on the analytical expression for the localization length derived for the case of weakly fluctuating widths of layers, that also takes into account possible correlations in disorder. We analyze how the correlations lead to anomalous properties of transport. In particular, we show that for quarter stack layered media specific correlations can result in a $\omega^2$-dependence of the Lyapunov exponent in all spectral bands. 
F.M.Izrailev and N.M.Makarov