Abstract
Nowadays the light-matter interaction phenomena in spatially periodic structure have been studied extensive, i.e. photonic crystals, cavity array. In this thesis, we consider coherent properties of coupled atom-field systems with adding the interaction between atoms and discuss the quantum phase transition and envelope function method for this system. We further show that beyond widely used low excitation density limit and Holstein-Primakoff transformation. We have shown that the phase transition diagram of the normal to superfluid (BEC) state of low branch polaritons in the critical temperature domain. Finally, a multiple-scale technique has been used to analyze the electromagnetic properties of the nonlinear dielectric periodic thin-film stacks. We have found a solitary–wave equation behavior in the array which includes the atom-atom interaction.