Spectral broadening and post-compression of amplified Yb:KGW oscillator pulses at 76 MHz repetition rate

We present pulse compression by double-pass spectral broadening in ZnS, KGW and YAG crystals pumped with 16 W average power amplified Yb:KGW oscillator pulses at a 76 MHz repetition rate. We demonstrate nearly transform-limited compressed laser pulses with excellent spatio-spectral homogeneity of the beam. This relatively simple and cost-effective method for pulse compression is applicable to almost any high-average power and low pulse energy laser system. It has the potential to open the opportunities for applications in ultrafast spectroscopy systems operating at pulse repetition rates in the tens or hundreds of MHz.