Gas- and bulk-based nonlinear pulse compression of 10 mJ and 50 W pulses of an ultrafast thin-disk amplifier.

We present a comparative study on nonlinear pulse compression of 10 mJ pulses from a thin-disk amplifier at 5 kHz in a multipass cell using both gaseous and bulk nonlinear media. First, we demonstrate compressibility from 465 fs to 34 fs in an argon filled multipass cell. We then replace the nonlinear medium by bulk material and operate in vacuum. In the latter case and using a single-pass setup, we demonstrate pulse compressibility in bulk material down to 84 fs. Finally, a double-pass configuration is implemented to further enhance spectral broadening, yielding to sub-50 fs pulse durations. Our results establish bulk-based multipass cells as a promising approach to overcoming length scaling limitations of gas-based multipass cell systems for high-energy nonlinear pulse compression.