Sub-50 fs temporal resolution in an FEL-optical laser pump-probe experiment at FLASH2

Area of Science:

• Ultrafast science
• Laser physics
• Particle accelerators

Background:

• High temporal resolution is crucial for ultrafast pump-probe experiments.
• Controlling arrival time jitter and drift is critical when synchronizing X-ray free-electron lasers (FELs) with optical lasers.
• Large-scale facilities and distinct pulse generation processes in FELs exacerbate timing challenges.

Purpose of the Study:

• To present and evaluate a laser pulse arrival time monitor for active correction of optical laser timing.
• To improve the temporal resolution of pump-probe experiments by synchronizing optical lasers with FELs.
• To demonstrate the effectiveness of the developed system through benchmark measurements.

Main Methods:

• Application of a laser pulse arrival time monitor to actively correct optical laser arrival time relative to the FEL's optical clock.
• Implementation of post-analysis single pulse jitter correction.
• Benchmark measurements using photo-ionization of xenon atoms at the FLASH beamline FL26.

Main Results:

• Significant improvement in temporal resolution for pump-probe experiments.
• Demonstration of sub-50 fs Full Width at Half Maximum (FWHM) overall temporal resolution.
• Successful synchronization of optical lasers with the FEL's main optical clock.

Conclusions:

• The developed laser pulse arrival time monitor effectively corrects optical laser timing relative to FELs.
• The combined active correction and post-analysis jitter correction significantly enhances temporal resolution.
• The system enables unprecedented temporal resolution for ultrafast pump-probe experiments using FELs.