High temporal contrast frontend with optical parametric amplifier for high powerful femtosecond laser

• We report a new method for generating high temporal contrast frontend.
• It combines the advantages of OPA and XPW at the same time.
• It can provide a long-term working reliability.
• It also provides a potential way to achieve broad spectrum and high energy.
• A HCF in vacuum is used to achieve beam profile improved.

We demonstrate a new method for generating reliable ultrashort 800 nm laser pulse with high temporal contrast. The experimental setup is based on the combination of hollow core fiber, cross-polarized wave generation and optical parametric amplifier. Laser pulses with pulse duration of <30 fs, energy of 60 μJ at a repetition rate of 1 kHz are generated. The temporal contrast has reached >1011 at ~10 ps before the main pulse. High temporal contrast, broad spectrum and the potential high energy of this system make it a reliable frontend for a high powerful femtosecond laser system.