Experimental and numerical study of direct sub-20fs multi-pass-cell post-compression of up to 4mJ, 80W Yb-based lasers

In recent years, various methods for laser pulse post-compression have demonstrated their effectiveness. Nonlinear spectral broadening, achieved by coupling an ultrafast pulse into a gas-filled multi-pass cell (MPC), typically enables pulse compression factors exceeding 20, depending on the initial pulse duration. In this work, we report the direct post-compression of four Yb-based commercial laser systems to sub-20 fs durations, with energies up to 4 mJ and initial pulse durations ranging from 320 fs to 450 fs, using argon-filled MPCs. Each MPC was specifically designed to operate at a fixed optimal point for each laser, achieving the shortest possible pulse duration. Numerical simulations reproducing the experimental data highlight the critical influence of the driver pulse’s temporal profile on the shape of the broadened spectra. These simulations are compared with the experimental results, demonstrating strong agreement.