QUANTITATIVE STUDY OF EXCITONIC POLARITON REFLECTANCE IN CDS .2. B-EXCITON AND K-LINEAR TERM

The influence of κ‐linear terms on the reflectivity spectra of excitonic polaritons is discussed for the case of the Γ5‐states of the B‐exciton of CdS. Using Pekar's abc and a dispersion relation consisting of three transverse and two longitudinal modes an effective index of refraction n* for oblique incidence of light is calculated. Spatial dispersion, the damping constant, the surface layer thickness, and the κ‐linear term are considered simultaneously. The energy parameters of the B‐exciton, especially the κ‐linear term, are deduced from the lineshape analysis of carefully measured reflectivity spectra. The structured spectra of the double resonance allow the more distinct investigation of the small discrepancies between theory and experiment still existing in the model of excitonic polaritons. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA