See subsection ‘High-power femtosecond oscillator and generation of waveform-stable MIR Pulses’ in Supplementary Information section I for details. a, HWP, half-wave plate; QWP, quarter-wave plate; IDFG, intra-pulse difference frequency generation; IDT, interferometric delay tracking; Ge, germanium beam combiner. All steering mirrors for the MIR beam were gold-coated. In the bandwidth-optimized instrument setting, four custom dispersive mirrors were added to the MIR beam path (see text). The pulse was temporally compressed with customized dispersive optics. Pulse compression. EOS traces of the excitation pulse transmitted through water in the bandwidth-optimized instrument setting, with (blue) and without (red) four dispersive mirrors in the MIR beam path. c, As in b but on a logarithmic scale, visualizing the improved roll-off of the signal achieved with the dispersive optics.