Ultrafast Coherent Dynamics of Fano Resonances in Semiconductors

Abstract

We present the first investigation of the ultrafast dynamics of the coherent emission from Fano resonances in semiconductors. Time-resolved femtosecond four-wave mixing (FWM) in GaAs under high magnetic field shows that dephasing is dominated by the coupling between discrete states and continua responsible for the Fano interference. In striking contrast to atomic systems and Lorentzian excitations in semiconductors, the decay of the time-integrated FWM signal is not related to dephasing. This decay is due to quantum interference originating from the interplay between semiconductor many-body effects and Fano interference.