Status quo and outlook of power scaling of ultrafast lasers

We demonstrate a compact diode-pumped Yb:YAG Innoslab femtosecond oscillator-amplifier system with nearly transform and diffraction limited 636 fs pulses at 620 W average output power and 20 MHz repetition rate. By cascading two amplifiers an output power of 1.1 kW and peak power of 80 MW is achieved. To our knowledge this is the highest average power for fs-pulses reported up to now. The system is operated at room temperature and no CPA technique is used.