60 fs, 1030 nm FEL pump-probe laser based on a multi-pass post-compressed Yb:YAG source.

Area of Science:

• Laser Physics
• Nonlinear Optics
• Ultrafast Science

Background:

• High-repetition-rate pump-probe experiments require ultrashort optical pulses.
• Existing methods face limitations in achieving both high average power and short pulse durations simultaneously.

Purpose of the Study:

• To develop a method for generating sub-100 femtosecond (fs) optical pulses at high average powers.
• To enable advanced pump-probe experiments at the free-electron laser FLASH.

Main Methods:

• Nonlinear spectral broadening of 1.1 picosecond (ps) pulses in a gas-filled multi-pass cell.
• Utilizing a 100 kHz Yb:YAG laser with 180 W in-burst average power.
• Employing a post-compression platform for pulse duration reduction.

Main Results:

• Generation of sub-100 fs optical pulses at 1030 nm with 0.8 mJ pulse energy.
• Generation of sub-100 fs optical pulses at 515 nm with 225 µJ pulse energy.
• Simultaneous achievement of high average powers and short pulse durations.

Conclusions:

• The developed method effectively generates ultrashort optical pulses suitable for high-repetition-rate FEL pump-probe experiments.
• This technique advances the capabilities for ultrafast scientific investigations using free-electron lasers.