Numerical investigation of gas-filled multipass cells in the enhanced dispersion regime for clean spectral broadening and pulse compression

We show via numerical simulations that the regime of enhanced frequency chirp can be achieved in gas-filled multipass cells. Our results demonstrate that there exists a region of pulse and cell parameters for which a broad and flat spectrum with a smooth parabolic-like phase can be generated. This spectrum is compatible with clean ultrashort pulses, whose secondary structures are always below the 0.5% of its peak intensity such that the energy ratio (the energy contained within the main peak of the pulse) is above 98%. This regime makes multipass cell post-compression one of the most versatile schemes to sculpt a clean intense ultrashort optical pulse.

Automated summary

We demonstrate through numerical simulations that enhanced frequency chirp can be achieved in gas-filled multipass cells. Our findings show that there is a parameter range for pulse and cell conditions where a broad and flat spectrum with a smooth parabolic-like phase can be generated. This spectrum is compatible with clean ultrashort pulses, with secondary structures always below 0.5% of the peak intensity, and an energy ratio above 98% for the main peak of the pulse. This makes multipass cell post-compression one of the most versatile schemes for shaping clean intense ultrashort optical pulses.