Experimental observation of superdiffusive transport in random dimer lattices

We experimentally observe anomalous wavepacket evolution in a realization of a one-dimensional finite binary Anderson model in the presence of short-range correlations. To this end, we employ weakly-coupled optical waveguides with propagation constants epsilon1 and epsilon2. The correlations enforce the creation of dimers, i.e. two adjacent waveguides with the same epsilon, randomly placed along the lattice. A transition from a ballistic to a superdiffusive wavepacket expansion and, eventually, to localization is observed as the contrast between the two propagation constants increases.