Résumé
CdMnTe quantum well embedded in CdMgTe/CdMnTe microcavity is studied by time-resolved Kerr rotation experiments under in-plane magnetic field and quantum beatings corresponding to at least three distinct frequencies are observed. Whereas the lowest gigahertz frequency is clearly identified with Mn spin precession in the quantum well, terahertz beatings can be due to both polariton formation and valence band states mixing in the magnetic field. However, the experiments indicate unambiguously that there is no beatings between coherently excited polariton states in the absence of magnetic field, in contrast with the proposed model, which predicts the beatings at Rabi frequency in zero field. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.