Polariton-polariton scattering in semiconductor microcavities: Experimental observation of thresholdlike density dependence

Baars, T Bayer, M Forchel, A Schafer, F Reithmaier, JP

T. Baars et al., Polariton-polariton scattering in semiconductor microcavities: Experimental observation of thresholdlike density dependence, PHYS REV B, 61(4), 2000, pp. R2409-R2412

20

INGLESE

Article

Apllied Physucs/Condensed Matter/Materiales Science

PHYSICAL REVIEW B

1098-0121 → ACNP

61

4

2000

R2409 - R2412

ISI

1098-0121(20000115)61:4<R2409:PSISME>2.0.ZU;2-S

Polariton-polariton scattering in semiconductor microcavities has been stud ied by time-integrated, degenerate four-wave mixing using spectrally compre ssed pulses. We find a thresholdlike behavior for the density dependence of the scattering rate gamma in the lower polariton branch. At low densities scattering is suppressed due to the small density of final states for the s cattering process. At higher density gamma increases as excitonlike states become accessible for the scattering and the scattering strength only depen ds on the exciton fraction of the initial states. The threshold density dep ends on the detuning between the polariton branches. The experimental findi ngs are in qualitative agreement with calculations using the self-consisten t Born approximation.