Light Dispersion in Diamond-like Crystals

Abstract

Dispersion of light in diamond-like crystals is investigated. Dispersion laws of exciton polaritons in this structures, which (apart from the diamond itself) include silicon and germanium is obtained within the quasi-molecular model of valent crystals. Dispersion curves point to the fact that in the vicinity of exciton resonance under small damping one must account for the exciton-photon interaction. The calculation shows that in a certain frequency range the existence of an additional light wave is possible. The dispersion laws of exciton polaritons in a diamond-like structure in the vicinity of frequency of the lowest dipole transition of a crystalline quasi-molecule (a σ-bond) are obtained.