Spatial coherence effects of stochastic optical beams in periodic potentials

The interaction between a partially coherent field with a one-dimensional periodic photonic environment is investigated within the framework of Floquet-Bloch modes. To this end, we describe the interplay between lattice properties and field fluctuations by considering the optical beam as a linear combination of Floquet-Bloch modes, whose coefficients are described by a stationary random process. It is demonstrated that the propagation of partially coherent beams depends not only on the average of the excitation of each band but also on the correlations existent among the various bands supported by the lattice.