Temporal behavior of biexciton luminescence under two-photon excitation in CuCl quantum dots

Temporal behavior of luminescence of biexcitons under two-photon resonant excitation has been measured in CuCl quantum dots. The non-exponential decay profile was observed, and its fast decay component becomes dominant with shortening the decay time for higher pump intensity. This characteristic feature of the biexciton emission is observable only for the two-photon resonant excitation with realization of population inversion in biexciton-exciton system at the initial stage and indicates the possibility of Dicke's superradiance, which is originated from the coherent interaction of diploes among many quantum dots.