Seeding of Polariton Stimulation in a Homogeneously Broadened Microcavity

In time-resolved light emission from a high-quality semiconductor microcavity after pulsed excitation suitable for angle-resonant polariton-polariton scattering on the lower-polariton branch, we find strong evidence for final-state stimulation of this process. The self-stimulated emission, following single-pulse excitation, appears on a fast time scale of only a few lens of ps with a maximum at 15 ps.

This is in striking contrast to the photoluminescence decay time of 110 ps observed in the low-density limit. By injection of polaritons into the final state by a seeding pulse, the dynamics and the intensity of this emission can be controlled. The time-resolved data and the density dependences are in agreement with a rate equation model neglecting polarization mixing effects.

This model gives a coupling coefficient of b(LP,k)=0 = 2.4 x 10(-9) cm(4) s(-1) for the stimulated angle-resonant polariton-polariton scattering process.