Abstract
The spontaneous-emission rate is evaluated for dipole emitters situated in the thin slab region between two semi-infinite one-dimensionally periodic photonic crystals, a situation reminiscent of planar cavity laser structures. It is pointed out that the long-wavelength electromagnetic fields supported by such complex structures can be directly quantized provided that the pair of semi-infinite photonic crystals are treated within the effective-medium approach, in which each photonic crystal is represented by a truncated uniaxial medium whose dielectric tensor components are determinable in terms of layer thicknesses and dielectric functions of the individual photonic crystal components. The spontaneous-emission rate is evaluated for a dipole emitter situated in the slab region, and oscillating at a frequency resonant with one of the modes that are localized within the slab and exponentially decaying within the photonic crystals. Both symmetric and asymmetric structures are discussed. Interesting features are predicted when the variations of the adjustable parameters are examined, including suppression and enhancement of the spontaneous rate.