title: Femtosecond coherent dynamics of the fermi-edge singularity and exciton hybrid.
abstract: We study theoretically the coherent nonlinear optical response of doped quantum wells with several subbands. When the Fermi energy approaches the exciton level of an upper subband, the absorption spectrum acquires a characteristic double-peak shape originating from the interference between the Fermi-edge singularity and the exciton resonance. We demonstrate that, for off-resonant pump excitation, the pump-probe spectrum undergoes a striking transformation, with a time-dependent exchange of oscillator strength between the Fermi-edge singularity and exciton peaks. This effect originates from the many-body electron-hole correlations which determine the dynamical response of the Fermi sea.
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA.
authors.forename: T V
authors.initials: TV
authors.lastname: Shahbazyan
authors.forename: N
authors.initials: N
authors.lastname: Primozich
authors.forename: I E
authors.initials: IE
authors.lastname: Perakis
authors.forename: D S
authors.initials: DS
authors.lastname: Chemla