Near the orthoexciton resonance in Cu2 O, light propagating through the medium is accompanied by a quadrupolar polarization, a quadrupole polariton. However, these orthoexciton-polaritons can lose their initial coherence because the excitonic component of the mode, a tightly bound electron-hole pair, is subject to wide-angle scattering by atomic-scale imperfections within the crystal. In order to examine this scattering by ambient impurities, we measured the angular dependence of the orthoexciton-polariton luminescence under resonant two-photon excitation at 2 K. A rather broad angular distribution is obtained at higher impurity concentrations. We provide a simplified polariton scattering model in order to describe the observed angular distribution. Various experimental data obtained from two natural-growth samples indicate that the orthoexciton-polariton propagation can strongly depend on the local impurity concentration.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Oct 31 2007|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics