Cavity-polariton photoluminescence in semiconductor microcavities: Experimental evidence

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Abstract
We have studied in detail the photoluminescence (PL) from a microcavity in the strong-coupling regime. The measurements were taken at 115 K, where the thermal energy is of the order of the cavity-polariton splitting. We observe several features: The photoluminescence is thermalized, in that it is identical to the absorption multiplied by a Boltzmann occupancy factor. There is strong cavity pulling, that is the maximum PL intensity is observed away from resonance and furthermore, it is the photonlike line that has the most intense luminescence. The spectrally integrated edge-emitted PL shows no variation with detuning, implying that the overall lifetime does not change with detuning. The spectrally integrated front surface PL has a Lorentzian variation. We try to explain all these features using two models, one of an uncoupled exciton in a cavity, the second of a coupled-mode, cavity polariton. We show that while the former describes many PL features, only the latter can give a full description. © 1996 The American Physical Society.