Wavelength-tunable split-and-delay optical system for hard X-ray free-electron lasers.

Area of Science:

• Optics and photonics
• Materials science
• X-ray physics

Background:

• Generating precisely timed X-ray pulses is crucial for advanced scientific research.
• Existing methods for temporal separation of X-ray pulses have limitations in stability and flexibility.

Purpose of the Study:

• To develop a stable and flexible hard X-ray split-and-delay optical (SDO) system.
• To enable variable temporal separation of X-ray pulses for time-resolved studies.

Main Methods:

• Designed an SDO system with variable-delay and fixed-delay branches.
• Fabricated high-quality thin and channel-cut crystals using plasma chemical vaporization machining.
• Developed a simple alignment method for spatial overlap of split pulses.

Main Results:

• The SDO system achieved a wide photon energy range (6.5-11.5 keV) and extensive delay times (up to 220 ps).
• Excellent spatial overlap of split pulses (30 nm accuracy) was demonstrated for focused beams.
• The system demonstrated high stability and operational flexibility.

Conclusions:

• The developed hard X-ray SDO system is a significant advancement for time-resolved X-ray studies.
• This technology facilitates femtosecond to subnanosecond time-resolved experiments at X-ray free-electron laser facilities.