Indirect observation of single-exciton quantum beats in the time-resolved reflection of a single quantum well

Oscillations in the time-resolved reflection of a single (In,Ga)/As/GaAs quantum well containing a single exciton resonance have been obtained by a numerical Fourier transform of a complex amplitude reflection coefficient restored from thermally detected optical absorption spectra recorded at 0.35 K. The observation is in excellent agreement with a recent theoretical prediction of beats in time-resolved optical spectra of single QWs (L.C. Andreani, G. Panzarini, A.V. Kavokin, M.R. Vladimirova, Phys. Rev. B 57 (1998) 4670).