FLASH free-electron laser single-shot temporal diagnostic: terahertz-field-driven streaking

Abstract

The commissioning of a terahertz-field-driven streak camera installed at the free-electron laser (FEL) FLASH at DESY in Hamburg, being able to deliver photon pulse duration as well as arrival time information with $ 10 fs resolution for each single XUV FEL pulse, is reported. Pulse durations between 300 fs and <15 fs have been measured for different FLASH FEL settings. A comparison between the XUV pulse arrival time and the FEL electron bunch arrival time measured at the FLASH linac section exhibits a correlation width of 20 fs r.m.s., thus demonstrating the excellent operation stability of FLASH. In addition, the terahertz-streaking setup was operated simultaneously to an alternative method to determine the FEL pulse duration based on spectral analysis. FLASH pulse duration derived from simple spectral analysis is in good agreement with that from terahertz-streaking measurement.

Non-invasive online wavelength measurements at FLASH2 and present benchmark

“…Moreover, temporal information such as the FEL pulse duration and arrival time can be determined with techniques involving streaking of photoelectrons by an external THz field (Grguraš et al, 2012). The latter scheme is currently implemented at FLASH (Ivanov et al, 2018). Here, the temporal information is projected onto the electron kinetic energy scale.…”

Characterization of soft X-ray FEL pulse duration with two-color photoelectron spectroscopy

“…For this purpose, several techniques in the temporal and frequency domain have been developed (Radcliffe et al, 2007;Frü hling et al, 2009;Mitzner et al, 2009;Moshammer et al, 2011;Inubushi et al, 2012;Grguraš et al, 2012;Dü sterer et al, 2014;Ivanov et al, 2018;Inoue et al, 2019;Kubota et al, 2019). In the temporal domain, one of the most straightforward methods to measure the X-ray pulse duration is cross-correlation with an optical laser.…”

THz streak camera performance for single-shot characterization of XUV pulses with complex temporal structures

“…A time-consuming THz-XUV delay scan that is essential for the characterization of the THz field needs to be performed only prior to the measurement. The single-shot capability of the streak camera motivated the efforts towards its integration into the beamline photon diagnostics at several user facilities [34][35][36]. The high interest of the photon science community to streak camera measurements at FEL and other laser facilities triggers a high demand on the efficient data analysis procedures that are able to extract time information from a limited number of measurements [20,37].…”