Observation of bottleneck effects on the photoluminescence from polaritonsin II-VI microcavities

The photoluminescence dynamics of microcavity polaritons are investigated b y ps time-resolved measurements as a function of the photon-exciton detunin g in the low, non-resonant excitation regime. For negative detuning, we obs erve the appearance of a relaxation slow-down accompanied by a build-up of a non-equilibrium polariton population on the exciton-like part of the lowe r branch. Finally, the role in the PL dynamics of the dark excitonic states existing in microcavities containing several quantum wells as alternative relaxation channels is addressed. (C) 1999 Elsevier Science B.V. All rights reserved.