Coherent Excitation of Polaritons in Gallium Phosphide

Abstract

The coherent excitation of polaritons has been achieved in the III-V semiconductor GaP for the first time by a nonlinear, optical parametric process. We are able to describe the polariton dispersion curve in the $\omega -k$ space and to measure the absorption coefficient of the crystal near the Reststrahl band. The results are discussed on the basis of recent theories on the polariton disperson and damping in GaP.