Two-colour hard X-ray free-electron laser with wide tunability

Area of Science:

• Atomic, Molecular, and Chemical Physics
• Plasma Physics
• Astrophysics
• Quantum Optics

Background:

• X-ray free-electron lasers (XFELs) provide ultrabrilliant, femtosecond pulses for studying matter interactions and observing minute targets.
• Current XFEL experiments primarily use single X-ray beams, limiting enhanced capabilities.
• Utilizing multiple X-ray beams with optimized parameters can significantly advance XFEL potential.

Purpose of the Study:

• To introduce a novel two-color double-pulse (TCDP) hard X-ray source.
• To demonstrate enhanced XFEL capabilities through flexible wavelength separation and attosecond-level temporal control.
• To enable the investigation of X-ray-induced ultrafast electronic transitions.

Main Methods:

• Development of a TCDP XFEL light source utilizing variable-gap undulators.
• Achieving large wavelength separation (>30%) and precise attosecond time intervals.
• Generating sub-10-femtosecond pulses with multi-gigawatt peak powers.

Main Results:

• Successful generation of a TCDP hard X-ray source with significant wavelength tunability.
• Demonstration of ultra-precise temporal control in the attosecond regime.
• Establishment of a powerful tool for probing ultrafast X-ray-matter interactions.

Conclusions:

• The TCDP XFEL scheme significantly enhances the capability of XFELs for advanced research.
• This technology is crucial for elucidating ultrafast transitions in electronic states and structures.
• Potential applications span ultrafast chemistry, plasma and astronomical physics, and quantum X-ray optics.