Propagation of Light in Doped Media with Regular and Random Distributed Clusters

Abstract

Macroscopic optical and low-frequency dielectric properties of a two-component composite medium composed of the impurities (clusters) embedded in a host medium are considered. Because of attractive forces sometimes there is an appreciable tendency for impurity particles in doped media to aggregate in cluster structures of various forms. Earlier, the problem of the clusters’ influence on the optical properties of doped materials was considered in the framework of the effective medium approximation, when media both inside and outside of clusters are treated as continuous ones ^1,2. Effective-medium theories differ only in the choice of host material and assume that inclusions are spherical and noninteracting. However, in actual heterogeneous materials clusters may have a complex shape and, as it was stated in Ref.¹, “the shape of particles [clusters] determines how effectively they are screened, which effects the microscopic polarization and fields”.