Free-electron laser temporal diagnostic beamline FL21 at FLASH

Area of Science:

• * Physics
• * Ultrafast Science
• * Free-Electron Laser Technology

Background:

• * Free-electron lasers (FELs) like the Free-Electron Laser in Hamburg (FLASH) produce intense, ultra-short extreme ultraviolet (XUV) pulses.
• * These XUV pulses exhibit shot-to-shot fluctuations inherent to the FEL operating principle.
• * Accurate characterization of these fluctuations requires single-shot diagnostic capabilities.

Purpose of the Study:

• * To design, construct, and implement a dedicated beamline for temporal diagnostics of XUV femtosecond pulses at FLASH.
• * To develop and integrate a terahertz field-driven streaking setup for single-shot pulse characterization.
• * To investigate the feasibility of parasitic operation modes for the diagnostic beamline.

Main Methods:

• * Implementation of a terahertz field-driven streaking technique within the diagnostic beamline.
• * Single-shot measurement of XUV pulse duration and arrival time.
• * Detailed characterization of beamline parameters and diagnostic setup performance.

Main Results:

• * Successful operation of the designed beamline for temporal diagnostics.
• * Demonstration of single-shot determination of XUV pulse duration and arrival time.
• * Presentation of initial experimental results validating the diagnostic capabilities.

Conclusions:

• * The new beamline effectively addresses the need for single-shot temporal diagnostics of fluctuating XUV FEL pulses.
• * The terahertz streaking setup provides a robust method for characterizing femtosecond XUV pulse properties.
• * Further investigations into parasitic operation concepts show promise for efficient use of FEL beam time.