Transition from the strong- to the weak-coupling regime in semiconductor microcavities:: Polarization dependence

The dependence on the polariton spin orientation of the transition from the strong- to the weak-coupling regime in InGaAs semiconductor microcavities is experimentally studied by means of time-resolved photoluminescence. Polaritons are nonresonantly excited by circularly polarized pulses and the photoluminescence of the K-parallel to similar to 0 states is analyzed into its co- and cross-polarized components. The loss of strong coupling with increasing excitation intensity takes place at different powers for polaritons with opposite spin orientation and it is determined by the polariton population of each spin. (C) 2007 American Institute of Physics.