Coherent control of resonant Rayleigh scattering

Phase-locked pulse pairs are used for resonant excitation of excitons confi ned within GaAs/AlGaAs quantum wells. The time-resolved secondary emission displays strong dependence on the relative phases of the two pulses for int er-pulse delays of the order of Ips or less. Constructive interference is c ombined with an increase in the rise time of the emission following the sec ond pulse. For longer inter-pulse delays the different phases of inhomogene ous excitons complicate the effect of the second pulse, with the apparent e ffect changing with time after the second pulse. To model this, the optical Bloch equations for a line of three-level systems are integrated over time and the resulting polarisations summed over a range of angles. The importa nce of the inhomogeneity in descriptions of coherent control of secondary e mission is shown.