Cr:ZnS-based soliton self-frequency shifted signal generation for a tunable sub-100 fs MWIR OPCPA

We present a tunable, high-energy optical parametric chirped pulse amplification system with a front-end based on a femtosecond Cr:ZnS laser. By taking advantage of the broad emission spectrum of the femtosecond Cr:ZnS master oscillator, we are able to directly seed the holmium-based pump around 2 mu m. At the same time, the signal pulses for the parametric process are generated via Raman self-frequency shifting of the red end of the spectrum centered at 2.4 mu m. The solitons, generated in a fluoride fiber, are tunable over the wavelength range between 2.8 and 3.2 mu m. The optical parametric amplifier operates at a 1 kHz repetition rate, and consists of two stages equipped with ZGP as nonlinear crystal. The generated idler pulses are tunable between 5.4 and 6.8 mu m with a pulse energy of up to 400 mu J. Dispersion management using bulk material stretching and compression in combination with precise phase shaping prior to amplification enables idler pulses of a sub-100 fs duration, translating into a peak power as high as 4 GW. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

We present a tunable, high-energy optical parametric chirped pulse amplification system with a front-end based on a femtosecond Cr:ZnS laser. The system uses the broad emission spectrum of the femtosecond Cr:ZnS master oscillator for direct seeding the pump and Raman self-frequency shifting for generating the signal pulses. The tunable idler pulses generated in fluoride fiber have a wavelength range of 2.8-3.2 μm.