Anomalous Dispersion of Excitonic Polariton Due to the Giant Two-Photon Absorption into Excitonic Molecule in CuCl

Abstract

The energy dependence of excitonic-polariton Raman lines upon the exciting laser energy has been found to show anomalous behavior when the excitation energy crosses the giant two-photon absorption band responsible for the direct generation of excitonic molecules. The anomalous behavior is ascribed to the non-linear change of the incident polariton dispersion.