Quantum theory of the interaction of quantum-well excitons with electromagnetic waveguide modes

We investigate the influence of the dielectric mismatch between barrier material and well material on the properties of excitonic polaritons in quantum wells. A quantum theory of the interaction between quantum-well excitons and dielectric waveguide eigenmodes is presented and polariton dispersion, radiative decay rate, and polariton eigenstates are obtained. The modifications as compared to previous theories are mainly a photonlike dispersion of the upper polariton branch for energies above the excitonic resonance as well as a finite imaginary part of the exciton self-energy for all values of ${\mathit{Q}}_{\mathrm{\parallel }}$. This theory can easily be extended to a description of structures with a more complicated profile of the dielectric constant.