Collective effects of multi-scatterer on coherent propagation of photon   in a two dimensional network
  We study the collective phenomenon in the scattering of a single-photon by one or two layers of two-level atoms. By modeling the photon dispersion with a two-dimensional (2D) coupled cavity array, we analytically derive the scattering probability of a single-photon. It is discovered that in the case with one layer of atoms, the atomic collective excitation leads to a shift for the single-photon scattering spectrum. Such a shift is related to the density of the atomic ensemble. For the case with two layers of atoms, an inter-layer effective coupling appears and induces an electromagnetic-induced-transparency-like phenomenon for the single-photon scattering. Our result provides a new scheme of analyzing photon coherent transport in 2D and may help to understand the current experiments about the high energy photon scattering by the layer nuclei material. 
D. Z. Xu, Yong Li, C. P. Sun, and Peng Zhang
quant-ph