Coherence and nonlinearity of femtosecond secondary emission from excitons in GaAs quantum wells

Summary form only given.We have investigated the nature and dynamics of resonant secondary emission from quantum wells, a subject of considerable current interest, using a novel approach in which the sample is resonantly excited by a pair of phase-locked pulses, and the emission is detected by femtosecond upconversion. This technique allows us to probe the dynamics of photoexcited polarization from a distinct perspective and gives new insights in the femtosecond dynamics of secondary emission (SE) and its coherence properties simultaneously.