Tunable ultrafast infrared generation in a gas-filled hollow-core capillary by a four-wave mixing process

In this paper, we numerically and experimentally investigate the four-wave mixing process in a gas-filled hollow-core capillary in the femtosecond regime. The interaction between a visible broadband continuum and a chirped pump pulse resulted in the generation of a tunable near-infrared pulse of 1.2 to 1.5 mu m and with the potential to reach the midinfrared range. Numerical simulations were performed in order to fully understand the role of key parameters such as the gas pressure, chirps, and relative delays of the involved pulses. The experimentation, which demonstrated and highlighted the feasibility of the tunable femtosecond source, led to the generation of an idler at 1.2 mu m with a duration of similar to 220 fs at the direct output of the capillary. The duration can ultimately be reduced to 45 fs in the presence of phase compensators. (C) 2022 Optica Publishing Group