Nonlinear quantum beat spectroscopy of bound biexcitons in II–VI semiconductors

Abstract With the technique of nonlinear quantum beat spectroscopy (NQBS), based on time-integrated, spectrally resolved four-wave mixing, the nonlinearities of biexcitons localized at neutral acceptor sites in CdSe are investigated. The NQBS offers the possibility to distinguish between quantum beats from a three-level system and polarization interference from independent two-level systems. The localized biexciton states are discussed in analogy with excited states of holes in neutral donor complexes.