Absorption quantum beats of magnetoexcitons in GaAs heterostructures

Abstract
We report the experimental observation of a transient oscillatory behavior of magnetoexciton absorption in GaAs/AlGaAs heterostructures. We interpret these oscillations as absorption quantum beats of a coherent superposition of two excitonic spin states. Measurements of the oscillations period may be used as a new technique for accurately measuring the Landé g factor of excitons in semiconductors.