@article{KimShahCunninghametal.1992, author = {Kim, Dai-Sik and Shah, Jagdeep and Cunningham, J. E. and Damen, T. C. and Sch{\"a}fer, Wilfried and Hartmann, Michael and Schmitt-Rink, Stefan}, title = {Giant excitonic resonance in time-resolved four-wave mixing in quantum wells}, series = {Physical Review Letters}, volume = {68}, journal = {Physical Review Letters}, pages = {1006 -- Keine Angabe - No details}, year = {1992}, abstract = {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.}, language = {en} }