Systematic study of peak power scaling for an Yb-doped Kerr-lens mode-locked bulk oscillator

We study systematically and experimentally the peak power scalability of a femtosecond Yb:YAG bulk oscillator with separate Kerr and gain medium. We demonstrate that small resonator modifications result in a peak power increase from 93 to 424 kW, corresponding to a repetition rate decrease from 70 to 11 MHz while keeping the pulse duration mostly constant in the range of 90-100 fs. The results are of importance for designing and building up femtosecond oscillators for different applications requiring different repetition rates, such as multiphoton microscopy and ultra-broadband infrared radiation generation.