CPA-free femtosecond thin disk Yb: KYW regenerative amplifier with high repetition rate

We report of an Yb:KYW thin disk amplifier system to provide ultra short pulses with high energies at high repetition rates. The thin disk concept uses large laser beam cross sections to avoid high peak intensities. Without using the chirped pulse amplification technique, pulse energies of about 100 µJ with pulse durations of 750 fs were generated at repetition rates of up to 45 kHz. Gires-Tournois interferometer mirrors are used in the amplifier resonator to avoid pulse stretching during amplification.