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Threshold behavior in the collision broadening of microcavity polaritons

1998; American Physical Society; Volume: 58; Issue: 16 Linguagem: Inglês

10.1103/physrevb.58.r10123

1095-3795

Cristiano Ciuti, Vincenzo Savona, Carlo Piermarocchi, A. Quattropani, P. Schwendimann,

Plasmonic and Surface Plasmon Research

The problem of the density-dependent homogeneous broadening of microcavity polaritons due to exciton-exciton Coulomb interaction is addressed using the self-consistent Born approximation. The theoretical results predict that, for resonant pumping of the lower polariton, the dependence of its broadening on the density of excitations has a threshold behavior. Below the threshold density, scattering is strongly inhibited because it involves only the small region of $k$ space where the polariton effective mass is very light. Above threshold, the region of $k$ space with excitonlike dispersion becomes allowed, giving the dominant contribution to the collision broadening.