Pulse Duration of Seeded Free-Electron Lasers

Finetti, P.; Höppner, Hauke; Allaria, E.; Callegari, Carlo; Capotondi, Flavio; Cinquegrana, Paolo; Coreno, Marcello; Cucini, Riccardo; Danailov, M. B.; Demidovich, Alexander; Ninno, G. De; Fraia, Michele Di; Feifel, Raimund; Ferrari, Eugenio; Fröhlich, Lars; Gauthier, David; Golz, Torsten; Grazioli, Cesare; Kai, Yuichi; Kurdi, G.; Mahne, Nicola; Manfredda, Michele; Medvedev, Nikita; Nikolov, Ivaylo; Pedersoli, Emanuele; Penco, G.; Plekan, Oksana; Prandolini, M. J.; Prince, Kevin C.; Raimondi, Lorenzo; Rebernik, P.; Riedel, Robert; Roussel, Eléonore; Sigalotti, Paolo; Squibb, Richard J.; Stojanović, Nikola; Stranges, Stefano; Svetina, Cristian; Tanikawa, Takanori; Teubner, U.; Tkachenko, Victor; Toleikis, S.; Zangrando, Marco; Ziaja, Beata; Tavella, F.; Giannessi, L.

doi:10.1103/physrevx.7.021043

Cited by 76 publications

(93 citation statements)

References 102 publications

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“…This electron bunch, generated in double-stage compression and without the HH cavity, has been driven along the FEL-1 line to lase in the high gain harmonic generation mode [31], obtaining an intensity and a spectral purity comparable to the ones characterizing FERMI in the nominal conditions. Figure 4 shows the single-shot FEL spectrum acquired at 25.9 nm: a relative bandwidth of about 3.4 × 10 −4 has been measured that is close to the Fourier limit and consistent with the typical FERMI output [32]. The exponential growth of the output intensity versus the number of resonant radiators has been measured by progressively detuning each radiator undulator (see the inset of Fig.…”

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confidence: 63%

Passive Linearization of the Magnetic Bunch Compression Using Self-Induced Fields

et al. 2017

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International audienceIn linac-driven free-electron lasers, colliders, and energy recovery linacs, a common way to compress the electron bunch to kiloampere level is based upon the implementation of a magnetic dispersive element that converts particle energy deviation into a path-length difference. Nonlinearities of such a process are usually compensated by enabling a high harmonic rf structure properly tuned in amplitude and phase. This approach is however not straightforward, e.g., in C-band and X-band linacs. In this Letter we demonstrate that the longitudinal self-induced field excited by the electron beam itself is able to linearize the compression process without any use of high harmonic rf structure. The method is implemented at the FERMI linac, with the resulting high quality beam used to drive the seeded free-electron laser during user experiments

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confidence: 63%

Passive Linearization of the Magnetic Bunch Compression Using Self-Induced Fields

et al. 2017

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“…Thus in this case the jitter is significantly less than the X-ray and NIR pulse durations, allowing for an even more precise measurement of the X-ray pulse duration [86]. Generally, the sideband method has been extensively used at FERMI to characterize the pulse length, and its results are in agreement with a complementary method and with theory [59]. A few distinctive aspects of its use at FERMI are related to the fact that this is a seeded source, resulting in predictable timing and coherence of the pulses.…”

Section: Sideband Methods For X-ray Pulse Characterizationmentioning

confidence: 89%

Ultrashort Free-Electron Laser X-ray Pulses

et al. 2017

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For the investigation of processes happening on the time scale of the motion of bound electrons, well-controlled X-ray pulses with durations in the few-femtosecond and even sub-femtosecond range are a necessary prerequisite. Novel free-electron lasers sources provide these ultrashort, high-brightness X-ray pulses, but their unique aspects open up concomitant challenges for their characterization on a suitable time scale. In this review paper we describe progress and results of recent work on ultrafast pulse characterization at soft and hard X-ray free-electron lasers. We report on different approaches to laser-assisted time-domain measurements, with specific focus on single-shot characterization of ultrashort X-ray pulses from self-amplified spontaneous emission-based and seeded free-electron lasers. The method relying on the sideband measurement of X-ray electron ionization in the presence of a dressing optical laser field is described first. When the X-ray pulse duration is shorter than half the oscillation period of the streaking field, few-femtosecond characterization becomes feasible via linear streaking spectroscopy. Finally, using terahertz fields alleviates the issue of arrival time jitter between streaking laser and X-ray pulse, but compromises the achievable temporal resolution. Possible solutions to these remaining challenges for single-shot, full time-energy characterization of X-ray free-electron laser pulses are proposed in the outlook at the end of the review.

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“…Existing temporal pulse property methods for FEL pulses in the soft and hard x-ray regime adapting measurement principles developed for optical fs-laser pulses, like the autocorrelation [7] or SPIDER [8] technique. Recently, the duration of pulses from the seeded FEL FERMI has been determined using nonlinear cross-correlation with an infrared laser pulse [9] and a chirp has been indirectly inferred by successively following the change in the FEL pulse duration, when modifying the chirp of the seed beam [10]. In the work presented here, we aimed at a direct measurement of the temporal properties of a seeded FEL pulse by employing the THz streak camera principle [11], which provides information on both pulse duration as well as spectral chirp [12].…”

Section: Introductionmentioning

confidence: 99%

Direct measurement of the pulse duration and frequency chirp of seeded XUV free electron laser pulses

et al. 2018

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We report on a direct time-domain measurement of the temporal properties of a seeded free-electron laser pulse in the extreme ultraviolet spectral range. Utilizing the oscillating electromagnetic field of terahertz radiation, a single-shot THz streak-camera was applied for measuring the duration as well as spectral phase of the generated intense XUV pulses. The experiment was conducted at FLASH, the free electron laser user facility at DESY in Hamburg, Germany. In contrast to indirect methods, this approach directly resolves and visualizes the frequency chirp of a seeded free-electron laser (FEL) pulse. The reported diagnostic capability is a prerequisite to tailor amplitude, phase and frequency distributions of FEL beams on demand. In particular, it opens up a new window of opportunities for advanced coherent spectroscopic studies making use of the high degree of temporal coherence expected from a seeded FEL pulse.

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Pulse Duration of Seeded Free-Electron Lasers

Cited by 76 publications

References 102 publications

Passive Linearization of the Magnetic Bunch Compression Using Self-Induced Fields

Passive Linearization of the Magnetic Bunch Compression Using Self-Induced Fields

Ultrashort Free-Electron Laser X-ray Pulses

Direct measurement of the pulse duration and frequency chirp of seeded XUV free electron laser pulses

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