A quantitative study of excitonic polariton reflectance in CdS

Abstract

Abstract A careful quantitative analysis of the reflectance of CdS crystals in the spectral range of the A‐exciton is presented. Measured spectra for the isotropic and the mixed‐mode orientation of the crystal are fitted by calculations based on the model of excitonic polaritons. Spatial dispersion and Pekar's abc, damping, exciton‐free surface layers, and oblique incidence of light are considered simultaneously. The good agreement between theory and experiment confirms the model, the still existing discrepancies are due to the simplifying assumption of a homogeneous surface layer. The formulae needed are summarized, and the influence of the different polariton parameters on the calculated reflectivity spectra are discussed.