title: Single-shot pulse duration monitor for extreme ultraviolet and X-ray free-electron lasers.
abstract: The resolution of ultrafast studies performed at extreme ultraviolet and X-ray free-electron lasers is still limited by shot-to-shot variations of the temporal pulse characteristics. Here we show a versatile single-shot temporal diagnostic tool that allows the determination of the extreme ultraviolet pulse duration and the relative arrival time with respect to an external pump-probe laser pulse. This method is based on time-resolved optical probing of the transient reflectivity change due to linear absorption of the extreme ultraviolet pulse within a solid material. In this work, we present measurements performed at the FLASH free-electron laser. We determine the pulse duration at two distinct wavelengths, yielding (184±14) fs at 41.5 nm and (21±19) fs at 5.5 nm. Furthermore, we demonstrate the feasibility to operate the tool as an online diagnostic by using a 20-nm-thin Si3N4 membrane as target. Our results are supported by detailed numerical and analytical investigations.
authors.affiliation: Universität Hamburg, Hamburg, Germany. robert.riedel@desy.de
authors.forename: R
authors.initials: R
authors.lastname: Riedel
authors.forename: A
authors.initials: A
authors.lastname: Al-Shemmary
authors.forename: M
authors.initials: M
authors.lastname: Gensch
authors.forename: T
authors.initials: T
authors.lastname: Golz
authors.forename: M
authors.initials: M
authors.lastname: Harmand
authors.forename: N
authors.initials: N
authors.lastname: Medvedev
authors.forename: M J
authors.initials: MJ
authors.lastname: Prandolini
authors.forename: K
authors.initials: K
authors.lastname: Sokolowski-Tinten
authors.forename: S
authors.initials: S
authors.lastname: Toleikis
authors.forename: U
authors.initials: U
authors.lastname: Wegner
authors.forename: B
authors.initials: B
authors.lastname: Ziaja
authors.forename: N
authors.initials: N
authors.lastname: Stojanovic
authors.forename: F
authors.initials: F
authors.lastname: Tavella