COHERENT CONTROL OF THE OPTICAL ORIENTATION OF EXCITONS IN QUANTUM-WELLS

We demonstrate that the optical orientation of excitons can be coheren tly controlled and directly observed in a resonant time resolved photo luminescence experiment. The optical dephasing time of excitons, their longitudinal and transverse spin relaxation times, and their radiativ e lifetime, are measured with strictly the same experimental condition s. The measurements rely on the linear response of the crystal.