Femtosecond thin disk Yb:KYW regenerative amplifier without CPA

We demonstrate the potential of an Yb: KYW thin disk regenerative amplifier to provide ultra short pulses with high energies. 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 subpicosecond pulse width were generated at a repetition rate of 5 kHz. Positive dispersion in the amplifier is compensated by Gires-Tournois interferometer mirrors in the resonator amplifier to avoid pulse stretching during amplification.