Abstract

Recent experiments succeeded in sub-100 fs pulse generation from solid-state lasers by use of a saturable single-quantum- well absorber (SQW) yielding self-starting 34-fs pulses in a Tksapphire laser² as well as 90-fs pulses in a diode-pumped Cr:LiSAF laser.³ These experimental findings can hardly be explained by the common theoretical understanding of passive modelocking in solid-state lasers, which requires a fast saturable loss for stable pulse generation. The relaxation of the absorption bleaching in a GaAs quantum well at room temperature exhibits a bitemporal behavior where the fast component of about 200 fs owing to thermal ionization of the exzitons is remarkably slower than the meanwhile achieved pulse width in the experiments.

© 1996 Optical Society of America