Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Femtosecond coherent fields induced by many-particle correlations in transient four-wave mixing

Kohärente Felder im Femtosekundenbereich induziert durch Vielteilchen beim transienten Vier-Wellen-Mischen


Physical Review. B 53 (1996), No.24, pp.16429-16443
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
Journal Article
Fraunhofer IAF ()
heterostructure; Heterostruktur; III-V Halbleiter; III-V semiconductors; quantum wells

We present a unified microscopic approach to four-wave mixing (FWM) in semiconductors on an ultrashort time scale. The theory is valid for resonant excitation in the vicinity of the excitonic resonance and at low densities. The most important many-particle effects, i.e., static and dynamical exciton-exciton interaction as well as biexcitonic effects are incorporated. The internal fields resulting from these interaction processes give rise to pronounced many particle effects in FWM signals. Our results explain the dependence of FWM signals on the polarization geometry, especially if biexcitons contribute. Time-resolved (TR) FWM experiments show that the diffraction of the interaction induced fields dominate the FWM signals completely. This dominance of the interaction induced field at low temperatures is true regardless of density, detuning, or polarization geometry. While spectrally resolved FWM (FWM) shows biexcitonic or bound excitonic contributions under various experimental conditi ons, TR-FWM is always completely delayed, peaking roughly at the dephasing time after both beams passed through.