Periodically oscillating anderson localization in random photonic superlattices with resonant units

In strongly disordered systems, where Anderson localization is present, the mean transmittance () decays exponentially on average with increasing sample size. However, often shows large fluctuations originating from extremely rare occurrences of necklaces of resonantly coupled states, possessing almost unity transmission. We show in this study that in one-dimensional (1D) random photonic systems with resonant layers these fluctuations appear to be very regular and have a period defined by the localization length \xi of the system. We demonstrate that necklace states are the origin of these well-defined oscillations. We predict that in such a random system efficient transmission channels form regularly each time the increasing sample length fits so-called optimal-order necklaces and demonstrate the phenomenon through numerical experiments. Our results provide new insight into the physics of Anderson localization in random systems with resonant units