TY - JOUR A1 - Kim, Dai-Sik A1 - Shah, Jagdeep A1 - Cunningham, J. E. A1 - Damen, T. C. A1 - Schäfer, Wilfried A1 - Hartmann, Michael A1 - Schmitt-Rink, Stefan T1 - Giant excitonic resonance in time-resolved four-wave mixing in quantum wells JF - Physical Review Letters N2 - We report a strong (300:1) excitonic resonance in time-resolved (100 fs) four-wave mixing in GaAs quantum wells as a function of the incident photon energy and show that it results from the large difference in the dephasing rates of excitons and free carriers. We conclude that excitons dominate even when they make up only a small fraction of the excited states. These results, in conjuction with new results in exciton-phonon scattering, provide new insights into previous studies performed with spectrally broad ultrashort pulses. KW - Physics Y1 - 1992 N1 - Volltext aus urheberrechtlichen Gründen nicht verfügbar. Fulltext due to copyright not available. VL - 68 SP - 1006 EP - Keine Angabe - No details ER -