PbS quantum-dot-doped glasses for ultrashort-pulse generation

We investigate the use of PbS quantum-dot-doped glasses as saturable absorb ers for ultrashort-pulse lasers by means of absorption bleaching experiment s and numerical analysis of the pulse shaping process using the Haus' maste r equation. We explain the mode-locking mechanism and the limitations of th ese absorbers. The generation of transform-limited fs pulses is predicted b y soliton mode locking initiated by the absorption saturation of higher exc ited states of the quantum-dot saturable absorber. (C) 2000 American Instit ute of Physics. [S0003-6951(00)02801-1].