Self-starting 6.5-fs pulses from a Ti:sapphire laser using asemiconductor saturable absorber and double chirped mirrors

摘要

We demonstrate self-starting 6.5-fs pulses from anKerr-lens-mode-locked Ti:sapphire laser with an average output power ofn200 mW at a pulse repetition rate of 86 MHz. We have achieved anmode-locking buildup time of only 60 Μs, using a broad-bandnsemiconductor saturable absorber mirror to initiate the pulse formation.nThe dispersion has been compensated with a prism pair in combinationnwith improved double-chirped mirrors. The prism pair allows for thenflexible adjustment of both the duration and the center wavelength ofnthe pulse. The double-chirped mirrors show a high reflectivity betternthan 99.8% over the full bandwidth of 300 nm and a controlled groupndelay over more than 250 nm. The choice of a proper output coupler turnsnout to be critical for ultrashort pulse generation directly from thenlaser