Unlike the conventional theory of giant oscillator strength, the recently proposed bipolariton model describes two-photon excitation of an excitonic molecule in terms of resonant polariton-polariton Coulomb scattering. Using angle-resolved spectroscopy, we directly measure the angular dependence of the molecule luminescence under resonant two-photon excitation. We find that the observed photoluminescence is highly directional and well correlated with the propagation direction of the incident laser. This observation unambiguously supports the core idea of this model that replaces the idea of a biexciton by that of a mutually bound propagating polariton molecule.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Dec 10 2007|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics