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.