Abstract

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 pulse width obtainable from this laser and present pulse compression experiments that produce 17 fs pulses with 70 mW of average power. Recently, we have constructed a regenerative amplifier pumped by a cw argon ion laser and have generated 120 fs pulses with 1.2 μJ of energy. These pulses have been used to generate a continuum at a repetition rate of 200 kHz. Finally, we will report on the synchronization of two mode-locked Ti:sapphire lasers and demonstrate a technique for performing two color pump-probe experiments with better than 150 fs resolution.

© 1992 Optical Society of America