Femtosecond hole-burning and nonlinear dynamics of quantum-confined semiconductor-doped glasses

Nonlinear absorption spectra of quantum confined CdSe microcrystallites in glass are measured in a femtosecond pump-probe experiment at low temperatures. Simultaneous bleaching of the transitions, and an induced absorption at higher energy are observed. Spectral hole burning is observed as the pump is tuned through the transition. The system is modelled as spherical crystallites with one or two electron-hole pairs interacting through the Coulomb potential. A numerical matix diagonalization method predicts results essentially similar to the experiment and attributes them to state filling of the one-pair states, and generation of two-pair states.