PICOSECOND AND FEMTOSECOND PULSE GENERATION IN A REGENERATIVELY MODE-LOCKED TI-SAPPHIRE LASER

We have produced transform-limited pulses ranging from 100 ps to 40 fs duration from a Ti:sapphire laser. output powers in excess of 1 W and peak powers of 0.5 MW have been observed. We describe the technique of regenerative mode locking and present evidence that a transient with a peak power of more than 10 kW is required to initiate mode locking. The role of group velocity dispersion is highlighted and a value of -750 fs2 is measured for the group delay dispersion in an operating laser. We describe the limits on both the power and pulsewidth obtainable from this laser and present pulse compression experiments which produce 17 fs pulses with 70 mW of average power.