Photon echo from GaAs quantum wells measured through Fourier-transform spectral interferometry

A technique to time resolve the four-wave mixing (FWM) signal is presented using Fourier-transform spectral interferometry providing both amplitude and phase of the FWM signal. The first experiment stressed that the acquisition time is shorter and no echo photon was wasted in the linear multichannel technique. In the second experiment, the FWM signal occur just after the second exciting pulse and has a finite risetime equal to the dephasing time. A standard pump-probe measurement was also performed exhibiting a spectral broadening of the excitonic lines and obtained a remarkable agreement with the FWM data.