Ultrafast X-ray pulse characterization at free-electron lasers

Grguraš, Ivanka; Maier, Andreas R.; Behrens, C.; Mazza, Tommaso; Kelly, Thomas J.; Radcliffe, P.; Düsterer, S.; Kazansky, A. K.; Кабачник, Н. М.; Tschentscher, Th.; Costello, J. T.; Meyer, Michael; Hoffmann, Matthias C.; Schlarb, H.; Cavalieri, Adrian L.

doi:10.1038/nphoton.2012.276

Cited by 200 publications

(184 citation statements)

References 45 publications

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“…[1][2][3][4] Combined with recently developed and constantly improving time-sorting pump-probe techniques, they can probe the atomic or electronic dynamics in irradiated materials with a femtosecond resolution. 21,22,26 These outstanding experimental achievements rely on a good performance of various devices used in FEL experiments. Many of these devices, such as detectors, substrates, x-ray mirrors and diffractive optics, involve carbon-based materials, in particular diamond.…”

Section: Introductionmentioning

confidence: 99%

Nonthermal graphitization of diamond induced by a femtosecond x-ray laser pulse

2013

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Diamond irradiated with an ultrashort intense laser pulse in the regime of photon energies from soft up to hard x rays can undergo a phase transition to graphite. This transition is induced by an excitation of electrons from the valence band or from atomic deep shells of the material into its conduction band, which is followed by a transient rapid change of the interatomic potential. Such a nonthermal phase transition occurs on a femtosecond time scale, shortly after or even during the laser pulse. In this work we show that the duration of the graphitization depends on the incoming photon energy: the higher the photon energy is, the longer the secondary electron cascading which promotes the electrons into the conduction band will take. The transient kinetics of the electronic and atomic processes during the graphitization is analyzed in detail. The damage threshold fluence is calculated in the broad photon energy range and is found to be always ∼0.7 eV/atom in terms of the average dose absorbed per atom. It is confirmed that the temporal characteristics of a femtosecond laser pulse (at a fixed pulse duration and fluence) do not significantly influence the transient damage kinetics. Finally, the influence of an additional surface layer of high-Z material on the damage within diamond is discussed.

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Section: Introductionmentioning

confidence: 99%

Nonthermal graphitization of diamond induced by a femtosecond x-ray laser pulse

2013

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“…Most crucial for time-resolved studies are the pulse length and the arrival time jitter with respect to an optical laser. Terahertz streaking of photoelectrons generated by the FEL pulse passing through a low-pressure gas target seems to be one of the most promising methods for non-invasive measurements of these quantities (Fruehling et al, 2009;Tavella et al, 2011;Grguras et al, 2012). Other methods under development are cross-correlation methods, which are achieved by shining a portion of the beam of the optical pump-probe laser and the FEL at an oblique angle onto the same spot of a suitable material, which changes its optical properties on interaction with the FEL pulses, thus providing relative timing information (Gahl et al, 2008;Beye et al, 2012;Riedel et al, 2013;Harmand et al, 2013).…”

Section: Free-electron Lasersmentioning

confidence: 99%

The potential of future light sources to explore the structure and function of matter

Weckert¹

2014

Acta Cryst Sect A

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Structural studies in general, and crystallography in particular, have benefited and still do benefit dramatically from the use of synchrotron radiation. Lowemittance storage rings of the third generation provide focused beams down to the micrometre range that are sufficiently intense for the investigation of weakly scattering crystals down to the size of several micrometres. Even though the coherent fraction of these sources is below 1%, a number of new imaging techniques have been developed to exploit the partially coherent radiation. However, many techniques in nanoscience are limited by this rather small coherent fraction. On the one hand, this restriction limits the ability to study the structure and dynamics of non-crystalline materials by methods that depend on the coherence properties of the beam, like coherent diffractive imaging and X-ray correlation spectroscopy. On the other hand, the flux in an ultra-small diffraction-limited focus is limited as well for the same reason. Meanwhile, new storage rings with more advanced lattice designs are under construction or under consideration, which will have significantly smaller emittances. These sources are targeted towards the diffraction limit in the X-ray regime and will provide roughly one to two orders of magnitude higher spectral brightness and coherence. They will be especially suited to experiments exploiting the coherence properties of the beams and to ultra-small focal spot sizes in the regime of several nanometres. Although the length of individual X-ray pulses at a storage-ring source is of the order of 100 ps, which is sufficiently short to track structural changes of larger groups, faster processes as they occur during vision or photosynthesis, for example, are not accessible in all details under these conditions. Linear accelerator (linac) driven free-electron laser (FEL) sources with extremely short and intense pulses of very high coherence circumvent some of the limitations of present-day storage-ring sources. It has been demonstrated that their individual pulses are short enough to outrun radiation damage for single-pulse exposures. These ultra-short pulses also enable time-resolved studies 1000 times faster than at standard storage-ring sources. Developments are ongoing at various places for a totally new type of X-ray source combining a linac with a storage ring. These energy-recovery linacs promise to provide pulses almost as short as a FEL, with brilliances and multi-user capabilities comparable with a diffraction-limited storage ring. Altogether, these new X-ray source developments will provide smaller and more intense X-ray beams with a considerably higher coherent fraction, enabling a broad spectrum of new techniques for studying the structure of crystalline and non-crystalline states of matter at atomic length scales. In addition, the short X-ray pulses of FELs will enable the study of fast atomic dynamics and non-equilibrium states of matter.

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“…The terahertz (THz) streak camera (Grguraš et al, 2012;Frü hling et al, 2009) has the potential to deliver single-shot pulse duration information essentially wavelength independent and with a high dynamic range (in pulse duration and pulse energy). Furthermore, it is able to be operated with repetition rates up to several hundred kHz (potentially even MHz).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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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.

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Ultrafast X-ray pulse characterization at free-electron lasers

Cited by 200 publications

References 45 publications

Nonthermal graphitization of diamond induced by a femtosecond x-ray laser pulse

Nonthermal graphitization of diamond induced by a femtosecond x-ray laser pulse

The potential of future light sources to explore the structure and function of matter

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

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