All-solid-state high-peak-power Ti:sapphire laser system above 5-kHz repetition rate

We have developed an all-solid-state Ti:sapphire laser system, which produces 22-fs, 0.2-TW pulses at 5-kHz repetition rate. An average power of 22.2 W is the highest ever obtained in ultrashort laser sources. The serious thermal lensing due to high power pumping in a small area of Ti:sapphire crystal is controlled successfully by a stable quasi-cavity with two concave mirrors. The attempt to increase the repetition rate to 10 kHz is also described.