Background-Free Intensity Autocorrelation for Femtosecond X-Ray Pulses

Area of Science:

• Physics
• Ultrafast Science
• X-ray Optics

Background:

• Measuring ultrashort x-ray pulses is crucial for studying ultrafast phenomena.
• Existing methods often suffer from background noise, limiting temporal resolution.
• Femtosecond x-ray pulses require advanced diagnostic tools for characterization.

Purpose of the Study:

• To demonstrate a background-free intensity autocorrelation measurement for 10-keV femtosecond x-ray pulses.
• To achieve attosecond temporal resolution for x-ray pulse characterization.
• To verify temporal shaping of x-ray pulses using perfect crystals.

Main Methods:

• Utilizing x-ray second harmonic generation (XSHG) in a quasicollinear geometry.
• Employing a narrow phase-matching condition to selectively generate autocorrelation signals.
• Achieving a geometric time resolution of approximately 1 attosecond.

Main Results:

• Demonstrated background-free intensity autocorrelation measurements for femtosecond x-ray pulses.
• Successfully revealed temporal modifications of x-ray pulses using an Si(311) monochromator.
• Verified the capability of temporal shaping with perfect crystals.

Conclusions:

• The developed XSHG method provides a robust tool for background-free x-ray pulse autocorrelation.
• This technique enables precise characterization of x-ray temporal dynamics with attosecond resolution.
• The method shows potential applicability for characterizing attosecond x-ray pulses.