Versatile soft X-ray-optical cross-correlator for ultrafast applications.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Ultrafast Spectroscopy

Background:

• Understanding ultrafast phenomena in materials requires advanced diagnostic tools.
• Current methods for probing X-ray dynamics can be limited in energy range or require specific experimental conditions.

Purpose of the Study:

• To present a novel X-ray-optical cross-correlator capable of operating across a broad spectrum of X-ray energies.
• To demonstrate a technique for probing photoexcited coherent phonons with high temporal resolution.

Main Methods:

• Utilized a molybdenum-silicon superlattice as the core component for X-ray-optical cross-correlation.
• Analyzed intensity and position changes of superlattice Bragg peaks induced by photoexcitation of coherent phonons.
• Operated the device on picosecond (ps) and femtosecond (fs) timescales.

Main Results:

• Achieved high total X-ray reflectivity up to 50%.
• Observed transient signal changes exceeding 20%.
• Demonstrated applicability across a wide range of X-ray photon energies and excitation wavelengths.

Conclusions:

• The developed X-ray-optical cross-correlator offers a versatile and robust method for studying ultrafast dynamics.
• The technique is field- and temperature-independent, enhancing its practical utility.
• The device provides high sensitivity and broad applicability for advanced materials research.