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

Abstract

In this manuscript, we numerically and experimentally investigated the four-wave mixing process in a gas filled hollowcore capillary in the femtosecond regime. The interaction between a visible broad-band continuum and a chirped pump pulse resulted to the generation of a tunable near infrared pulse of 1.2 to 1.5 µm, and with the potentiality to reach the mid-infrared 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 µm with a duration of ~220 fs at the direct output of the capillary. The duration can ultimately be reduced to 45 fs in the presence of phase compensators.