Abstract
We present a quantum theory of interaction between quantum-well excitons and electromagnetic eigenmodes of a multilayer dielectric cavity. The coupled exciton-photon modes are obtained by analyzing the exciton spectral function. The design of the cavity allows us to obtain enhanced spontaneous emission or a normal-mode splitting. We find very good agreement with the normal-mode splitting data of Weisbuch et al. [Phys. Rev. Lett. 69, 3314 (1992)].