EXCITON-POLARITONS IN HALF-SPACE

A rigorous method is presented describing the coupling between an exci ton polariton in a halfspace semiconductor and the external driving fi eld. The method is based on density matrix theory. It allows to consid er realistic electron-hole interactions, spatial dispersion and extrin sic surface potentials. Without invoking additional boundary condition s or an artificial subdivision of the semiconductor it is shown that t he influence of the surface can be isolated from the bulk behaviour. T his is accomplished by a symmetric continuation of the restricted conf iguration space to bulk geometry inspired by the image source method i n electrostatics. As a demonstration the solution is worked out for a simplified polariton model. The results are compared with other theori es and with experimental reflection spectra.