Signatures of carrier multiplication in the frequency resolved fluorescence spectra from polaritons

Using the micro-cavity coupled to weakly confined excitons in quantum dots we investigated the signatures of carrier multiplication in the single and two-photon emitted frequency resolved fluorescence. Those are compared to the spectra provided by the conventional multi-photon induced fluorescence. The two processes are distinguished by the statistics of the initial polariton distribution. We argue that exciton emission spectra turned out to be CM insensitive, while the polaritons emission demonstrates strong spectral signatures of the CM. When the polaritonic effect dominates the confinement-boosted excitons' nonlinearities, increasing quantum yield leads to consecutive appearance of Rabi multiplets. The correlation spectra reveal the formation of more multiplets as compared to the single photon emission. When the confinement increases the multiplets start to overlap and their classification requires transient measurements of the spectral snapshots. These are based on the discrete Auger lifetimes of the multi-excitons.