Performance of a hard X-ray split-and-delay optical system with a wavefront division.

Area of Science:

• Optics and photonics
• X-ray science
• Free-electron laser technology

Background:

• Hard X-ray free-electron lasers (XFELs) require sophisticated optical systems for precise beam manipulation.
• Split-and-delay optical (SDO) systems are crucial for time-resolved experiments using XFELs.
• Wavefront division schemes offer a method for splitting and controlling X-ray beams.

Purpose of the Study:

• To investigate the performance of a hard X-ray split-and-delay optical (SDO) system utilizing a wavefront division scheme.
• To characterize the beam properties and assess the capabilities for manipulation and diagnostics.
• To evaluate the system's suitability for advanced X-ray experiments at facilities like SACLA.

Main Methods:

• Utilized edge-polished perfect Si(220) crystals as beam splitters for wavefront division.
• Employed non-invasive diagnostics for shot-to-shot pulse energy measurements.
• Characterized focal profiles and achieved spatial overlap of split beams.
• Measured pulse delay times using an X-ray streak camera and variable path length.

Main Results:

• Achieved shot-to-shot non-invasive diagnostics of pulse energies for both SDO branches.
• Obtained nearly ideal and identical focal profiles with a spot size of approximately 1.5 µm (FWHM).
• Attained sub-micrometer spatial overlap accuracy between the two focused beams.
• Confirmed reliable tunability of delay time with an accuracy of ±0.4 ps over a 60 ps range.

Conclusions:

• The hard X-ray SDO system with wavefront division demonstrates excellent performance for XFEL applications.
• The system enables precise beam manipulation, including sub-micrometer focusing and accurate spatial overlap.
• The demonstrated capabilities in pulse energy diagnostics and delay time control are vital for advanced time-resolved X-ray science.