FEMTOSECOND TIME-RESOLVED 4-WAVE-MIXING FROM BIEXCITONS IN GAAS QUANTUM-WELLS - DOMINANCE OF THE INTERACTION-INDUCED SIGNAL

Time-resolved (TR) four-wave mixing (FWM) experiments are performed on a high-quality GaAs quantum-well sample where biexcitons make the dominant contribution under certain experimental conditions. TR-FWM peaks well after both beams passed through, regardless of relative contributions of biexcitons to FWM. Our experiments show that the diffraction of the interaction-induced field dominates FWM from biexcitons, as well as from excitons.