Versatile optical laser system for experiments at the European X-ray free-electron laser facility.

Area of Science:

• Laser Physics
• Ultrafast Science
• X-ray Science

Background:

• Experiments at the European X-ray free-electron laser facility require synchronized optical laser systems.
• Existing laser systems may not meet the specific temporal and power demands for pump-probe experiments with femtosecond X-ray pulses.

Purpose of the Study:

• To present the final prototype of a pulsed optical laser system designed for integration with femtosecond X-ray free-electron laser (XFEL) beams.
• To detail the laser's capabilities, including its pulse characteristics, power output, and flexibility for various experimental configurations.

Main Methods:

• The laser system is synchronized to the temporal emission pattern of the XFEL facility.
• It operates in a burst mode with high intra-burst pulse frequencies and adjustable pulse durations.
• Configuration options allow for energy scaling and generation of nearly transform-limited pulses.

Main Results:

• The laser provides 10 Hz bursts of up to 600 µs duration with intra-burst frequencies up to 4.5 MHz.
• Pulses as short as 12 fs at 350 W average power (during burst) were generated at 800 nm, approaching the diffraction limit.
• This represents the highest power achieved for a few-cycle laser at 800 nm.
• Alternative configurations offer energy scaling to >3 mJ/pulse and pulse durations from 12 fs to 300 fs.
• A synchronized 1030 nm beam provides up to 4 kW burst average power (40 mJ/pulse at 100 kHz).

Conclusions:

• The developed pulsed optical laser is a highly capable and flexible tool for experiments utilizing XFELs.
• Its performance, including record power and tunable pulse characteristics, significantly enhances experimental possibilities.
• The laser's dual-wavelength capability and nonlinear conversion options further expand its utility in advanced research.