Dipole relaxation in dispersive photonic band-gap structures

Photonic structures are considered with the emphasis on dispersive materials and on one-dimensionally periodic structures. The electromagnetic frequency bands and the corresponding field distributions are determined for a GaAs/AlAs one-dimensional photonic structure and the field quantization is established. The interaction is considered between the electromagnetic fields and an oscillating electric dipole located deep within the layers. This involves coupling to the polariton modes of this inhomogeneous medium, with each type of mode providing a dipole relaxation channel. Relaxation processes due to emission into the polariton channels are analyzed. The results are displayed in terms of the emission rate {Γ} versus the dipole position Z₀ for a fixed dipole frequency ω₀ and against ω₀ for a fixed Z₀ . These results strongly indicate the existence of band-edge effects associated with the dispersive response of the materials comprising the layered system.