Light propagation in layered photonic crystals with admixture layers

The virtual-crystal approximation is used for numerical simulation of a polariton spectrum transformation in composite materials, consisting of alternating silicon and liquid crystal layers and randomly included admixture layers. The character of dependence of the bandgap width and the refractive index upon the concentra-tion of admixture layers is discussed. It is shown that the energy structure of this imperfect superlattice can be significantly altered by implantation of appropriate defect layers.