Femtosecond nonlinear spectroscopy of semiconductor quantum dots: effect of two-electron-hole-pair interaction

The authors report on measurements of the femtosecond dynamics of differential transmission spectra (DTS) of CdSe semiconductor nanocrystals excited well above the energy of the lowest optical transition. The effect of the two-pair interaction manifests itself at the initial stage of carrier relaxation, before the lowest electron and hole levels become occupied, as a red-shift of the lowest resonance in the nonlinear absorption spectra.<
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