Experimental studies of refractive-index dependence of exciton spontaneous decay rates

Abstract

The spontaneous decay rates of atoms can be altered by embedding them in a bulk dielectric medium. The alteration of the decay rates depends on three physical factors: a photon density of state factor, a local-field correction factor, and a field normalization factor. There are conflicting expressions in the literature for the local-field correction and field normalization factors. However, it is expected that for a thin slab a change in the total decay rate for an embedded atom or exciton should change when the slab thickness is approximately ( λ )/2πn. We are fabricating dielectric slabs with dimensions in this range that will allow us to demonstrate both the dependence of decay rate on the slab thickness and the index of the surrounding medium. Our experiment involves a technique for embedding thin GaAs/AlGaAs quantum well structures in different dielectric media with n ranging 1.5–3.5 and measuring the spontaneous decay rates.