Effective Cross Section Enhancement from Embedded Atomic Lattice Impurities*

Atoms arranged in a two-dimensional lattice strongly interact with light via collective excitations. Such lattices can be supplemented with impurity atoms which couple to the collective array modes and permit the manipulation of emission properties. In particular, the combination of strong array-light coupling and large impurity atom non-linearity enable highly nonlinear responses to collminated, far-field radiation. We explore the effective enhancement of impurity cross section which results from this coupling in a variety of lattice potentials and parameter regimes. Higher-order photon correlations are calculated and pertinet extensions, such as long-lived photon bound states and multi-impurity systems, are discussed.