Femtosecond time-evolution of the coherence properties of resonant secondary emission from excitons in GaAs quantum wells

The femtosecond dynamics and the coherence properties of resonant secondary emission (RSE) from quantum wells is a subject of considerable current interest. We use a novel approach in which the sample is resonantly excited by a pair of phase-locked pulses, and the spontaneously emitted radiation is detected by femtosecond upconversion. This novel experimental technique allows us, for the first time, to investigate the temporal evolution and the coherence properties of RSE simultaneously