ULTRAFAST PROCESSES IN SEMICONDUCTOR-DOPED GLASSES

We review studies of resonant and nonresonant ultrafast optical proces ses in semiconductor doped glasses, made at the University of Campinas . First we discuss measurements done in CdTe quantum-dots in glass, ex cited resonantly. In this case we observe a fast recombination, that d epends on the size of the quantum-dot. Far the smallest dots, with 3.2 nm average radius, the recovery time constant was found to be 360 fs. Then we describe the observation of the Optical Stark shift in CdSxSe 1-x semiconductor-doped glass (SDG) excited under nonresonant below ga p condition and probed with femtosecond optical pulses. An ultrafast a nd pure light-induced shift of the band edge is observed. For a pump i ntensity of 3 GW/cm(2) the band shifts by 11 meV. The response of the shift tracks the profile of the pumping pulse.