Abstract

Recently there has been much interest in the photoluminescence (PL) properties of semiconductor microcavities that exhibit normalmode coupling (MNC).¹ When a narrow line- width quantum well is grown inside a moderately high-finesse microcavity, the exci- ton-photon coupling results in two peaks in transmission when the cavity resonance and the exciton resonance coincide. When the cavity resonance is detuned above the exciton resonance energy and the microcavity is pumped above the mirror stopband, the PL exhibits a curious thresholdlike behavior: as the carrier density is increased, the upper- branch PL increases rapidly while the lower- branch PL tends to saturate. This behavior was attributed to the spontaneous buildup of exciton polariton population in a microcavity, i.e., an exciton polariton laser or boser,² based on final-state stimulation to a Bose condensate. The hope was that exciton polariton lasing would provide a source of coherent radiation with a threshold well below the lasing threshold.

© 1998 Optical Society of America