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Design of a Hybrid Split-Delay Line for Hard X-ray Free-Electron Lasers. PHOTONICS 2022. [DOI: 10.3390/photonics9030136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
High repetition-rate X-ray free-electron lasers (XFELs) enable the study of fast dynamics on microsecond time scales. Split-delay lines (SDLs) further bring the time scale down to femtoseconds by splitting and delaying the XFEL pulses. Crystals and multilayers are two common types of optical elements in SDLs, offering either long delay ranges or high temporal accuracy. In this work, we introduce the design of a hybrid SDL for the coherent diffraction endstation of Shanghai High Repetition Rate XFEL and Extreme Light Facility (SHINE). It uses crystals for the first branch and multilayers for the second one, thus simultaneously offering a relatively long delay range and high temporal accuracy. Moreover, a third branch can be installed to switch the SDL to the all-crystal configuration for longer delay ranges.
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2
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Shi S, Chen J, Yang Y, Yan ZC, Liu X, Wang B. Explanation of the anomalous redshift on a nonlinear X-ray Compton scattering spectrum by a bound electron. OPTICS EXPRESS 2022; 30:1664-1674. [PMID: 35209322 DOI: 10.1364/oe.448633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Nonlinear Compton scattering is an inelastic scattering process where a photon is emitted due to the interaction between an electron and an intense laser field. With the development of X-ray free-electron lasers, the intensity of X-ray laser is greatly enhanced, and the signal from X-ray nonlinear Compton scattering is no longer weak. Although the nonlinear Compton scattering by an initially free electron has been thoroughly investigated, the mechanism of nonrelativistic nonlinear Compton scattering of X-ray photons by bound electrons is unclear yet. Here, we present a frequency-domain formulation based on the nonperturbative quantum electrodynamics to study nonlinear Compton scattering of two photons by an atom in a strong X-ray laser field. In contrast to previous theoretical works, our results clearly reveal the existence of a redshift phenomenon observed experimentally by Fuchs et al.(Nat. Phys.)11, 964(2015) and suggest its origin as the binding energy of the electron as well as the momentum transfer from incident photons to the electron during the scattering process. Our work builds a bridge between intense-laser atomic physics and Compton scattering processes that can be used to study atomic structure and dynamics at high laser intensities.
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3
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Zastrau U, Appel K, Baehtz C, Baehr O, Batchelor L, Berghäuser A, Banjafar M, Brambrink E, Cerantola V, Cowan TE, Damker H, Dietrich S, Di Dio Cafiso S, Dreyer J, Engel HO, Feldmann T, Findeisen S, Foese M, Fulla-Marsa D, Göde S, Hassan M, Hauser J, Herrmannsdörfer T, Höppner H, Kaa J, Kaever P, Knöfel K, Konôpková Z, Laso García A, Liermann HP, Mainberger J, Makita M, Martens EC, McBride EE, Möller D, Nakatsutsumi M, Pelka A, Plueckthun C, Prescher C, Preston TR, Röper M, Schmidt A, Seidel W, Schwinkendorf JP, Schoelmerich MO, Schramm U, Schropp A, Strohm C, Sukharnikov K, Talkovski P, Thorpe I, Toncian M, Toncian T, Wollenweber L, Yamamoto S, Tschentscher T. The High Energy Density Scientific Instrument at the European XFEL. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1393-1416. [PMID: 34475288 PMCID: PMC8415338 DOI: 10.1107/s1600577521007335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
The European XFEL delivers up to 27000 intense (>1012 photons) pulses per second, of ultrashort (≤50 fs) and transversely coherent X-ray radiation, at a maximum repetition rate of 4.5 MHz. Its unique X-ray beam parameters enable groundbreaking experiments in matter at extreme conditions at the High Energy Density (HED) scientific instrument. The performance of the HED instrument during its first two years of operation, its scientific remit, as well as ongoing installations towards full operation are presented. Scientific goals of HED include the investigation of extreme states of matter created by intense laser pulses, diamond anvil cells, or pulsed magnets, and ultrafast X-ray methods that allow their diagnosis using self-amplified spontaneous emission between 5 and 25 keV, coupled with X-ray monochromators and optional seeded beam operation. The HED instrument provides two target chambers, X-ray spectrometers for emission and scattering, X-ray detectors, and a timing tool to correct for residual timing jitter between laser and X-ray pulses.
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Affiliation(s)
- Ulf Zastrau
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Karen Appel
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Carsten Baehtz
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Oliver Baehr
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | | | - Mohammadreza Banjafar
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | | | - Thomas E. Cowan
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Horst Damker
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | | | - Jörn Dreyer
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Hans-Olaf Engel
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | | | - Manon Foese
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | | | - Mohammed Hassan
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Jens Hauser
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | - Hauke Höppner
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Johannes Kaa
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- Technische Universität Dortmund, 44227 Dortmund, Germany
| | - Peter Kaever
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Klaus Knöfel
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | | | | | - Jona Mainberger
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Mikako Makita
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Emma E. McBride
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Dominik Möller
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | - Alexander Pelka
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | | | | | - Michael Röper
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | - Wolfgang Seidel
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | | | - Ulrich Schramm
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Andreas Schropp
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | | | | | - Peter Talkovski
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Ian Thorpe
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Monika Toncian
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | - Toma Toncian
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
| | | | - Shingo Yamamoto
- Helmholtz-Zentrum Dresden-Rossendorf eV, 01328 Dresden, Germany
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4
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de La Rochefoucauld O, Dovillaire G, Harms F, Idir M, Huang L, Levecq X, Piponnier M, Zeitoun P. EUV and Hard X-ray Hartmann Wavefront Sensing for Optical Metrology, Alignment and Phase Imaging. SENSORS 2021; 21:s21030874. [PMID: 33525501 PMCID: PMC7865934 DOI: 10.3390/s21030874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 12/27/2022]
Abstract
For more than 15 years, Imagine Optic have developed Extreme Ultra Violet (EUV) and X-ray Hartmann wavefront sensors for metrology and imaging applications. These sensors are compatible with a wide range of X-ray sources: from synchrotrons, Free Electron Lasers, laser-driven betatron and plasma-based EUV lasers to High Harmonic Generation. In this paper, we first describe the principle of a Hartmann sensor and give some key parameters to design a high-performance sensor. We also present different applications from metrology (for manual or automatic alignment of optics), to soft X-ray source optimization and X-ray imaging.
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Affiliation(s)
| | - Guillaume Dovillaire
- Imagine Optic, 18 rue Charles de Gaulle, 91400 Orsay, France; (G.D.); (F.H.); (X.L.); (M.P.)
| | - Fabrice Harms
- Imagine Optic, 18 rue Charles de Gaulle, 91400 Orsay, France; (G.D.); (F.H.); (X.L.); (M.P.)
| | - Mourad Idir
- Brookhaven National Laboratory, 50 Rutherford Drive, Upton, NY 11973, USA; (M.I.); (L.H.)
| | - Lei Huang
- Brookhaven National Laboratory, 50 Rutherford Drive, Upton, NY 11973, USA; (M.I.); (L.H.)
| | - Xavier Levecq
- Imagine Optic, 18 rue Charles de Gaulle, 91400 Orsay, France; (G.D.); (F.H.); (X.L.); (M.P.)
| | - Martin Piponnier
- Imagine Optic, 18 rue Charles de Gaulle, 91400 Orsay, France; (G.D.); (F.H.); (X.L.); (M.P.)
| | - Philippe Zeitoun
- Laboratoire d’Optique Appliquée, CNRS, ENSTA Paris, Ecole Polytechnique IP Paris, 91120 Palaiseau, France;
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5
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Pandey AK, Papagiannouli I, Sanson F, Baynard E, Demailly J, Kazamias S, Pittman M, Neveu O, Lucas B, Le Marec A, Klisnick A, Calisti A, Larroche O, Ros D, Guilbaud O. Towards subpicosecond pulses from solid target plasma based seeded soft X-ray laser. OPTICS EXPRESS 2020; 28:28924-28941. [PMID: 33114801 DOI: 10.1364/oe.399339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
We investigate the coherence of plasma-based soft X-ray laser (XRL) for different conditions that can alter the electron density in the gain region. We first measure the source temporal coherence in amplified spontaneous emission (ASE) mode. We develop a data analysis procedure to extract both its spectral width and pulse duration. These findings are in agreement with the spectral line shape simulations and seeded operation experimental results. Utilizing the deduced spectral width and pulse duration in a one-dimensional Bloch-Maxwell code, we reproduce the experimental temporal coherence properties of the seeded-XRL. Finally, we demonstrate efficient lasing in ASE and seeded mode at an electron density two times higher than the routine conditions. In this regime, using Bloch-Maxwell modeling, we predict the pulse duration of the seeded XRL to be ∼500fs.
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6
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Zhou G, Jiao Y, Raubenheimer TO, Wang J, Holman AJ, Tsai CY, Wu JY, Wu W, Yang C, Yoon M, Wu J. Coherence time characterization method for hard X-ray free-electron lasers. OPTICS EXPRESS 2020; 28:10928-10938. [PMID: 32403614 DOI: 10.1364/oe.28.010928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/10/2019] [Indexed: 06/11/2023]
Abstract
Coherence time is one of the fundamental characteristics of light sources. Methods based on autocorrelation have been widely applied from optical domain to soft X-rays to characterize the radiation coherence time. However, for the hard X-ray regime, due to the lack of proper mirrors, it is extremely difficult to implement such autocorrelation scheme. In this paper, a novel approach for characterizing the coherence time of a hard X-ray free-electron laser (FEL) is proposed and validated numerically. A phase shifter is adopted to control the correlation between X-ray and microbunched electrons. The coherence time of the FEL pulse can be extracted from the cross-correlation. Semi-analytical analysis and three-dimensional time-dependent numerical simulations are presented to elaborate the details. A coherence time of 218.2 attoseconds for 6.92 keV X-ray FEL pulses is obtained in our simulation based on the configuration of Linac Coherent Light Source. This approach provides critical temporal coherence diagnostics for X-ray FELs, and is decoupled from machine parameters, applicable for any photon energy, radiation brightness, repetition rate and FEL pulse duration.
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7
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Zhou G, Decker FJ, Ding Y, Jiao Y, Lutman AA, Maxwell TJ, Raubenheimer TO, Wang J, Holman AJ, Tsai CY, Wu JY, Wu W, Yang C, Yoon M, Wu J. Attosecond Coherence Time Characterization in Hard X-Ray Free-Electron Laser. Sci Rep 2020; 10:5961. [PMID: 32249769 PMCID: PMC7136262 DOI: 10.1038/s41598-020-60328-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/14/2019] [Indexed: 11/30/2022] Open
Abstract
One of the key challenges in scientific researches based on free-electron lasers (FELs) is the characterization of the coherence time of the ultra-fast hard x-ray pulse, which fundamentally influences the interaction process between x-rays and materials. Conventional optical methods, based on autocorrelation, are very difficult to realize due to the lack of mirrors. Here, we experimentally demonstrate a novel method which yields a coherence time of 174.7 attoseconds for the 6.92 keV FEL pulses at the Linac Coherent Light Source. In our experiment, a phase shifter is adopted to control the cross-correlation between x-ray and microbunched electrons. This approach provides critical diagnostics for the temporal coherence of x-ray FELs and is universal for general machine parameters; applicable for wide range of photon energy, radiation brightness, repetition rate and FEL pulse duration.
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Affiliation(s)
- Guanqun Zhou
- Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.,SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Franz-Josef Decker
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA
| | - Yuantao Ding
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA
| | - Yi Jiao
- Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Alberto A Lutman
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA
| | - Timothy J Maxwell
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA
| | - Tor O Raubenheimer
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA
| | - Jiuqing Wang
- Key Laboratory of Particle Acceleration Physics and Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Aaron J Holman
- Department of Physics and The Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA
| | - Cheng-Ying Tsai
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA.,Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jerome Y Wu
- Jane Lathrop Stanford Middle School, 480 E Meadow Dr, Palo Alto, CA, 94306, USA
| | - Weiwei Wu
- JSerra Catholic High School, 26351 Junipero Serra Road, San Juan Capistrano, CA, 92675, USA
| | - Chuan Yang
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA.,National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, China
| | - Moohyun Yoon
- Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Juhao Wu
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94309, USA.
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8
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Double-pulse speckle contrast correlations with near Fourier transform limited free-electron laser light using hard X-ray split-and-delay. Sci Rep 2020; 10:5054. [PMID: 32193442 PMCID: PMC7081363 DOI: 10.1038/s41598-020-61926-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/04/2020] [Indexed: 11/08/2022] Open
Abstract
The ability to deliver two coherent X-ray pulses with precise time-delays ranging from a few femtoseconds to nanoseconds enables critical capabilities of probing ultra-fast phenomena in condensed matter systems at X-ray free electron laser (FEL) sources. Recent progress made in the hard X-ray split-and-delay optics developments now brings a very promising prospect for resolving atomic-scale motions that were not accessible by previous time-resolved techniques. Here, we report on characterizing the spatial and temporal coherence properties of the hard X-ray FEL beam after propagating through split-and-delay optics. Speckle contrast analysis of small-angle scattering measurements from nanoparticles reveals well-preserved transverse coherence of the beam. Measuring intensity fluctuations from successive X-ray pulses also reveals that only single or double temporal modes remain in the transmitted beam, corresponding to nearly Fourier transform limited pulses.
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9
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Foglia L, Capotondi F, Höppner H, Gessini A, Giannessi L, Kurdi G, Lopez Quintas I, Masciovecchio C, Kiskinova M, Mincigrucci R, Naumenko D, Nikolov IP, Pedersoli E, Rossi GM, Simoncig A, Bencivenga F. Exploring the multiparameter nature of EUV-visible wave mixing at the FERMI FEL. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2019; 6:040901. [PMID: 31372368 PMCID: PMC6663514 DOI: 10.1063/1.5111501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
The rapid development of extreme ultraviolet (EUV) and x-ray ultrafast coherent light sources such as free electron lasers (FELs) has triggered the extension of wave-mixing techniques to short wavelengths. This class of experiments, based on the interaction of matter with multiple light pulses through the Nth order susceptibility, holds the promise of combining intrinsic ultrafast time resolution and background-free signal detection with nanometer spatial resolution and chemical specificity. A successful approach in this direction has been the combination of the unique characteristics of the seeded FEL FERMI with dedicated four-wave-mixing (FWM) setups, which leads to the demonstration of EUV-based transient grating (TG) spectroscopy. In this perspective paper, we discuss how the TG approach can be extended toward more general FWM spectroscopies by exploring the intrinsic multiparameter nature of nonlinear processes, which derives from the ability of controlling the properties of each field independently.
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Affiliation(s)
- L Foglia
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - F Capotondi
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - H Höppner
- Institute for Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf e.V., 01328 Dresden, Germany
| | - A Gessini
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - L Giannessi
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - G Kurdi
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - I Lopez Quintas
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - C Masciovecchio
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - M Kiskinova
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - R Mincigrucci
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - D Naumenko
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - I P Nikolov
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - E Pedersoli
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - G M Rossi
- Physics Department and The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - A Simoncig
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - F Bencivenga
- Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy
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10
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Roseker W, Lee S, Walther M, Rysov R, Sprung M, Grübel G. Spatial and temporal pre-alignment of an X-ray split-and-delay unit by laser light interferometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:045106. [PMID: 31042974 DOI: 10.1063/1.5089496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 03/15/2019] [Indexed: 06/09/2023]
Abstract
We present a novel experimental setup for performing a precise pre-alignment of a hard X-ray split-and-delay unit based on low coherence light interferometry and high-precision penta-prisms. A split-and-delay unit is a sophisticated perfect crystal-optics device that splits an incoming X-ray pulse into two sub-pulses and generates a controlled time-delay between them. While the availability of a split-and-delay system will make ultrafast time-correlation and X-ray pump-probe experiments possible at free-electron lasers, its alignment process can be very tedious and time-consuming due to its complex construction. By implementing our experimental setup at beamline P10 of PETRA III, we were able to reduce the time of alignment to less than 3 h. We also propose an alternate method for finding the zero-time delay crossing without the use of X-rays or pulsed laser sources. The successful demonstration of this method brings prospect for operating the split-and-delay systems under alignment-time-critical environments such as X-ray free electron laser facilities.
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Affiliation(s)
- W Roseker
- Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - S Lee
- Frontier in Extreme Physics, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, South Korea
| | - M Walther
- Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - R Rysov
- Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - M Sprung
- Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - G Grübel
- Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
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11
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Coherence and pulse duration characterization of the PAL-XFEL in the hard X-ray regime. Sci Rep 2019; 9:3300. [PMID: 30824784 PMCID: PMC6397240 DOI: 10.1038/s41598-019-39765-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/28/2019] [Indexed: 11/08/2022] Open
Abstract
We characterize the spatial and temporal coherence properties of hard X-ray pulses from the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL, Pohang, Korea). The measurement of the single-shot speckle contrast, together with the introduction of corrections considering experimental conditions, allows obtaining an intrinsic degree of transverse coherence of 0.85 ± 0.06. In the Self-Amplified Spontaneous Emission regime, the analysis of the intensity distribution of X-ray pulses also provides an estimate for the number of longitudinal modes. For monochromatic and pink (i.e. natural bandwidth provided by the first harmonic of the undulator) beams, we observe that the number of temporal modes is 6.0 ± 0.4 and 90.0 ± 7.2, respectively. Assuming a coherence time of 2.06 fs and 0.14 fs for the monochromatic and pink beam respectively, we estimate an average X-ray pulse duration of 12.6 ± 1.0 fs.
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12
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Sauppe M, Rompotis D, Erk B, Bari S, Bischoff T, Boll R, Bomme C, Bostedt C, Dörner S, Düsterer S, Feigl T, Flückiger L, Gorkhover T, Kolatzki K, Langbehn B, Monserud N, Müller E, Müller JP, Passow C, Ramm D, Rolles D, Schubert K, Schwob L, Senfftleben B, Treusch R, Ulmer A, Weigelt H, Zimbalski J, Zimmermann J, Möller T, Rupp D. XUV double-pulses with femtosecond to 650 ps separation from a multilayer-mirror-based split-and-delay unit at FLASH. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:1517-1528. [PMID: 30179193 PMCID: PMC6140391 DOI: 10.1107/s1600577518006094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/20/2018] [Indexed: 06/08/2023]
Abstract
Extreme ultraviolet (XUV) and X-ray free-electron lasers enable new scientific opportunities. Their ultra-intense coherent femtosecond pulses give unprecedented access to the structure of undepositable nanoscale objects and to transient states of highly excited matter. In order to probe the ultrafast complex light-induced dynamics on the relevant time scales, the multi-purpose end-station CAMP at the free-electron laser FLASH has been complemented by the novel multilayer-mirror-based split-and-delay unit DESC (DElay Stage for CAMP) for time-resolved experiments. XUV double-pulses with delays adjustable from zero femtoseconds up to 650 picoseconds are generated by reflecting under near-normal incidence, exceeding the time range accessible with existing XUV split-and-delay units. Procedures to establish temporal and spatial overlap of the two pulses in CAMP are presented, with emphasis on the optimization of the spatial overlap at long time-delays via time-dependent features, for example in ion spectra of atomic clusters.
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Affiliation(s)
- Mario Sauppe
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Dimitrios Rompotis
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Benjamin Erk
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Tobias Bischoff
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Rebecca Boll
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Cédric Bomme
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Christoph Bostedt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA
- Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Simon Dörner
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Stefan Düsterer
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Torsten Feigl
- optiX fab GmbH, Hans-Knöll-Straße 6, 07745 Jena, Germany
| | - Leonie Flückiger
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- ARC Centre of Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe University, Melbourne 3086, Australia
| | - Tais Gorkhover
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- Stanford PULSE Institute, SLAC National Laboratory, Menlo Park, CA, USA
| | - Katharina Kolatzki
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Bruno Langbehn
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Nils Monserud
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Erland Müller
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Jan P. Müller
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Christopher Passow
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Daniel Ramm
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Daniel Rolles
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Kaja Schubert
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Lucas Schwob
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Björn Senfftleben
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Rolf Treusch
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Anatoli Ulmer
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Holger Weigelt
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Jannis Zimbalski
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Julian Zimmermann
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Thomas Möller
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Daniela Rupp
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
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13
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Suhasaria T, Thrower JD, Frigge R, Roling S, Bertin M, Michaut X, Fillion JH, Zacharias H. XUV photodesorption of carbon cluster ions and ionic photofragments from a mixed methane-water ice. Phys Chem Chem Phys 2018; 20:7457-7469. [PMID: 29488999 DOI: 10.1039/c8cp00171e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The photochemical processing of a CH4 : D2O 1 : 3.3 ice mixture adsorbed on an HOPG surface in the XUV regime was investigated using pulses obtained from the Free-electron LASer in Hamburg (FLASH) facility. Ice films were exposed to femtosecond pulses with a photon energy of hν = 40.8 eV, consistent with the HeII resonance line. Cationic species desorbing directly from the ice films were detected using time-of-flight (ToF) mass spectrometry. Simple ions formed through the fragmentation of the parent molecules and subsequent recombination reactions were detected and are consistent with efficient D+ and H+ ejection from the parent species, similar to the case for low energy electron irradiation. The FEL fluence dependencies of these ions are linear or exhibit a non-linear order of up to 3. In addition, a series of Cn+ cluster ions (with n up to 12) were also identified. These ions display a highly non-linear desorption yield with respect to the FEL fluence, having an order of 6-10, suggesting a complex multi-step process involving the primary products of CH4 fragmentation. Two-pulse correlation measurements were performed to gain further insight into the underlying reaction dynamics of the photo-chemical reactions. The yield of the D2O derived products displayed a different temporal behaviour with respect to the Cn+ ions, indicating the presence of very different reaction pathways to the two families of ionic products.
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Affiliation(s)
- T Suhasaria
- Physikalisches Institut, Westfälische Wilhelms Universität, Wilhelm Klemm Straße 10, 48149 Münster, Germany.
| | - J D Thrower
- Physikalisches Institut, Westfälische Wilhelms Universität, Wilhelm Klemm Straße 10, 48149 Münster, Germany.
| | - R Frigge
- Physikalisches Institut, Westfälische Wilhelms Universität, Wilhelm Klemm Straße 10, 48149 Münster, Germany. and Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität, 48149 Münster, Germany
| | - S Roling
- Physikalisches Institut, Westfälische Wilhelms Universität, Wilhelm Klemm Straße 10, 48149 Münster, Germany.
| | - M Bertin
- Sorbonne Université, Observatoire de Paris, PSL Research University, Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères, CNRS UMR 8112, 75005 Paris, France
| | - X Michaut
- Sorbonne Université, Observatoire de Paris, PSL Research University, Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères, CNRS UMR 8112, 75005 Paris, France
| | - J-H Fillion
- Sorbonne Université, Observatoire de Paris, PSL Research University, Laboratoire d'Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères, CNRS UMR 8112, 75005 Paris, France
| | - H Zacharias
- Physikalisches Institut, Westfälische Wilhelms Universität, Wilhelm Klemm Straße 10, 48149 Münster, Germany. and Center for Soft Nanoscience, Westfälische Wilhelms Universität, 48149, Münster, Germany
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14
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Capotondi F, Foglia L, Kiskinova M, Masciovecchio C, Mincigrucci R, Naumenko D, Pedersoli E, Simoncig A, Bencivenga F. Characterization of ultrafast free-electron laser pulses using extreme-ultraviolet transient gratings. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:32-38. [PMID: 29271748 DOI: 10.1107/s1600577517015612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/26/2017] [Indexed: 06/07/2023]
Abstract
The characterization of the time structure of ultrafast photon pulses in the extreme-ultraviolet (EUV) and soft X-ray spectral ranges is of high relevance for a number of scientific applications and photon diagnostics. Such measurements can be performed following different strategies and often require large setups and rather high pulse energies. Here, high-quality measurements carried out by exploiting the transient grating process, i.e. a third-order non-linear process sensitive to the time-overlap between two crossed EUV pulses, is reported. From such measurements it is possible to obtain information on both the second-order intensity autocorrelation function and on the coherence length of the pulses. It was found that the pulse energy density needed to carry out such measurements on solid state samples can be as low as a few mJ cm-2. Furthermore, the possibility to control the arrival time of the crossed pulses independently might permit the development of a number of coherent spectroscopies in the EUV and soft X-ray regime, such as, for example, photon echo and two-dimensional spectroscopy.
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Affiliation(s)
- F Capotondi
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - L Foglia
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - M Kiskinova
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - C Masciovecchio
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - R Mincigrucci
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - D Naumenko
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - E Pedersoli
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - A Simoncig
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
| | - F Bencivenga
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, I-34012 Basovizza, Trieste, Italy
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15
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Marec AL, Larroche O, Klisnick A. Linear autocorrelation of partially coherent extreme-ultraviolet lasers: a quantitative analysis. OPTICS LETTERS 2017; 42:4958-4961. [PMID: 29216155 DOI: 10.1364/ol.42.004958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/26/2017] [Indexed: 06/07/2023]
Abstract
A quantitative interpretation method is described for experiments involving the linear autocorrelation of partially coherent extreme-ultraviolet (XUV) pulses, generated by either x-ray free-electron lasers or plasma-based XUV lasers. A recently published modeling method for partially coherent pulses is numerically implemented in that specific case. Analytical expressions for the statistical root-mean-square average of the fringe visibility are derived. The method yields unambiguous information on both the coherence time and the pulse duration, providing a valuable data interpretation tool.
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16
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Osaka T, Hirano T, Morioka Y, Sano Y, Inubushi Y, Togashi T, Inoue I, Tono K, Robert A, Yamauchi K, Hastings JB, Yabashi M. Characterization of temporal coherence of hard X-ray free-electron laser pulses with single-shot interferograms. IUCRJ 2017; 4:728-733. [PMID: 29123674 PMCID: PMC5668857 DOI: 10.1107/s2052252517014014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/28/2017] [Indexed: 05/09/2023]
Abstract
Temporal coherence is one of the most fundamental characteristics of light, connecting to spectral information through the Fourier transform relationship between time and frequency. Interferometers with a variable path-length difference (PLD) between the two branches have widely been employed to characterize temporal coherence properties for broad spectral regimes. Hard X-ray interferometers reported previously, however, have strict limitations in their operational photon energies, due to the specific optical layouts utilized to satisfy the stringent requirement for extreme stability of the PLD at sub-ångström scales. The work presented here characterizes the temporal coherence of hard X-ray free-electron laser (XFEL) pulses by capturing single-shot interferograms. Since the stability requirement is drastically relieved with this approach, it was possible to build a versatile hard X-ray interferometer composed of six separate optical elements to cover a wide photon energy range from 6.5 to 11.5 keV while providing a large variable delay time of up to 47 ps at 10 keV. A high visibility of up to 0.55 was observed at a photon energy of 10 keV. The visibility measurement as a function of time delay reveals a mean coherence time of 5.9 ± 0.7 fs, which agrees with that expected from the single-shot spectral information. This is the first result of characterizing the temporal coherence of XFEL pulses in the hard X-ray regime and is an important milestone towards ultra-high energy resolutions at micro-electronvolt levels in time-domain X-ray spectroscopy, which will open up new opportunities for revealing dynamic properties in diverse systems on timescales from femto-seconds to nanoseconds, associated with fluctuations from ångström to nanometre spatial scales.
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Affiliation(s)
- Taito Osaka
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Takashi Hirano
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yuki Morioka
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yasuhisa Sano
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yuichi Inubushi
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Tadashi Togashi
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Ichiro Inoue
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Kensuke Tono
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Aymeric Robert
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 102, Menlo Park, CA 94025, USA
| | - Kazuto Yamauchi
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Jerome B. Hastings
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 102, Menlo Park, CA 94025, USA
| | - Makina Yabashi
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
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17
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Sakamoto J, Ohwada K, Ishino M, Mizuki J, Ando M, Namikawa K. Design of a prototype split-and-delay unit for XFEL pulses, and their evaluation by synchrotron radiation X-rays. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:95-102. [PMID: 28009550 DOI: 10.1107/s1600577516017744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
A prototype split-and-delay unit (SDU) for X-ray free-electron laser (XFEL) pulses is proposed based on the Graeff-Bonse four-Bragg-reflection interferometer by installing 12.5° slopes. The SDU can continuously provide a delay time from approximately -20 to 40 ps with a resolution of less than 26 fs. Because the SDU was constructed from a monolithic silicon crystal, alignment is straightforward. The obtained thoroughputs of the SDU reached 0.7% at 7.46 keV and 0.02% at 14.92 keV. The tunability of the delay time using the proposed SDU was demonstrated by finding the interference effects of the split X-rays, and the time resolution of the proposed SDU was evaluated using the width of the interference pattern recorded on the X-ray charge-coupled device camera by changing the energy, i.e. longitudinal coherence length, of the incident X-rays. It is expected that the proposed SDU will be applicable to XFEL experiments using delay times from tens of femtoseconds to tens of picoseconds, e.g. intensity correlation measurements.
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Affiliation(s)
- Jun'ya Sakamoto
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Kenji Ohwada
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Masahiko Ishino
- Department of Advanced Photon Research, Kansai Photon Science Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215, Japan
| | - Jun'ichiro Mizuki
- School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
| | - Masami Ando
- Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kazumichi Namikawa
- Tokyo Gakugei University, 4-1-1 Nukuikita-machi, Koganei, Tokyo 184-8501, Japan
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18
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Le Marec A, Guilbaud O, Larroche O, Klisnick A. Evidence of partial temporal coherence effects in the linear autocorrelation of extreme ultraviolet laser pulses. OPTICS LETTERS 2016; 41:3387-3390. [PMID: 27420542 DOI: 10.1364/ol.41.003387] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We study how the degree of temporal coherence of plasma-based extreme ultraviolet lasers operated in the amplification of the spontaneous emission mode is encoded in the shape of the linear autocorrelation function, which is obtained from the variation of the fringe visibility while varying the delay in a variable path-difference interferometer. We discuss the implications of this effect when the technique is used to infer the spectral properties of the source. Our numerical simulations, based on a partial coherence model developed by other authors for x-ray free electron lasers, are in good agreement with previously reported sets of measurements, illustrating similar statistical properties for both sources.
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19
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Ahad L, Vartiainen I, Setälä T, Friberg AT, David C, Makita M, Turunen J. On spectral and temporal coherence of x-ray free-electron laser beams. OPTICS EXPRESS 2016; 24:13081-13090. [PMID: 27410327 DOI: 10.1364/oe.24.013081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A model for the coherence properties of free-electron lasers (FELs) in time and frequency domains is introduced within the framework of classical second-order coherence theory of nonstationary light. An iterative phase-retrieval algorithm is applied to construct an ensemble of field realizations in both domains, based on single-pulse spectra measured at the Linac Coherent Light Source (LCLS) in self-amplified spontaneous emission mode. Such an ensemble describes the specific FEL pulse train in a statistically averaged sense. Two-time and two-frequency correlation functions are constructed, demonstrating that the hard X-ray free-electron laser at LCLS in this case behaves as a quasistationary source with low spectral and temporal coherence. We also show that the Gaussian Schell model provides a good description of this FEL.
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20
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Rath AD, Timneanu N, Maia FRNC, Bielecki J, Fleckenstein H, Iwan B, Svenda M, Hasse D, Carlsson G, Westphal D, Mühlig K, Hantke M, Ekeberg T, Seibert MM, Zani A, Liang M, Stellato F, Kirian R, Bean R, Barty A, Galli L, Nass K, Barthelmess M, Aquila A, Toleikis S, Treusch R, Roling S, Wöstmann M, Zacharias H, Chapman HN, Bajt S, DePonte D, Hajdu J, Andreasson J. Explosion dynamics of sucrose nanospheres monitored by time of flight spectrometry and coherent diffractive imaging at the split-and-delay beam line of the FLASH soft X-ray laser. OPTICS EXPRESS 2014; 22:28914-28925. [PMID: 25402130 DOI: 10.1364/oe.22.028914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We use a Mach-Zehnder type autocorrelator to split and delay XUV pulses from the FLASH soft X-ray laser for triggering and subsequently probing the explosion of aerosolised sugar balls. FLASH was running at 182 eV photon energy with pulses of 70 fs duration. The delay between the pump-probe pulses was varied between zero and 5 ps, and the pulses were focused to reach peak intensities above 10¹⁶W/cm² with an off-axis parabola. The direct pulse triggered the explosion of single aerosolised sucrose nano-particles, while the delayed pulse probed the exploding structure. The ejected ions were measured by ion time of flight spectrometry, and the particle sizes were measured by coherent diffractive imaging. The results show that sucrose particles of 560-1000 nm diameter retain their size for about 500 fs following the first exposure. Significant sample expansion happens between 500 fs and 1 ps. We present simulations to support these observations.
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21
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Siemer B, Roling S, Frigge R, Hoger T, Mitzner R, Zacharias H. Free-electron laser induced processes in thin molecular ice. Faraday Discuss 2014; 168:553-69. [PMID: 25302398 DOI: 10.1039/c3fd00116d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intermolecular reactions in and on icy films on silicate and carbonaceous grains constitute a major route for the formation of new molecular constituents in interstellar molecular clouds. In more diffuse regions and in protoplanetary discs, energetic radiation can trigger reaction routes far from thermal equilibrium. As an analog of interstellar ice-covered dust grains, highly-oriented pyrolytic graphite (HOPG) covered with D2O, NO, and H atoms is irradiated by ultrashort XUV pulses and the desorbing ionic and neutral products are analysed. The yields of several products show a nonlinear intensity dependence and thus enable the elucidation of reaction dynamics by two-pulse correlated desorption.
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22
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Singer A, Lorenz U, Sorgenfrei F, Gerasimova N, Gulden J, Yefanov OM, Kurta RP, Shabalin A, Dronyak R, Treusch R, Kocharyan V, Weckert E, Wurth W, Vartanyants IA. Hanbury Brown-Twiss interferometry at a free-electron laser. PHYSICAL REVIEW LETTERS 2013; 111:034802. [PMID: 23909331 DOI: 10.1103/physrevlett.111.034802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Indexed: 06/02/2023]
Abstract
We present measurements of second- and higher-order intensity correlation functions (so-called Hanbury Brown-Twiss experiment) performed at the free-electron laser (FEL) FLASH in the non-linear regime of its operation. We demonstrate the high transverse coherence properties of the FEL beam with a degree of transverse coherence of about 80% and degeneracy parameter of the order 10(9) that makes it similar to laser sources. Intensity correlation measurements in spatial and frequency domain gave an estimate of the FEL average pulse duration of 50 fs. Our measurements of the higher-order correlation functions indicate that FEL radiation obeys Gaussian statistics, which is characteristic to chaotic sources.
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Affiliation(s)
- A Singer
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg, Germany
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23
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Photoelectron Angular Distribution and Phase in Two-Photon Single Ionization of H and He by a Femtosecond and Attosecond Extreme-Ultraviolet Pulse. APPLIED SCIENCES-BASEL 2013. [DOI: 10.3390/app3010189] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Sobierajski R, Loch RA, van de Kruijs RWE, Louis E, von Blanckenhagen G, Gullikson EM, Siewert F, Wawro A, Bijkerk F. Mo/Si multilayer-coated amplitude-division beam splitters for XUV radiation sources. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:249-57. [PMID: 23412481 PMCID: PMC3573871 DOI: 10.1107/s0909049512049990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 12/06/2012] [Indexed: 05/23/2023]
Abstract
Amplitude-division beam splitters for XUV radiation sources have been developed and extensively characterized. Mo/Si multilayer coatings were deposited on 50 nm-thick SiN membranes. By changing the multilayer structure (periodicity, number of bilayers, etc.) the intensity of the reflected and transmitted beams were optimized for selected incident radiation parameters (wavelength, incident angle). The developed optical elements were characterized by means of XUV reflectometry and transmission measurements, atomic force microscopy and optical interferometry. Special attention was paid to the spatial homogeneity of the optical response and reflected beam wavefront distortions. Here the results of the characterization are presented and improvements required for advanced applications at XUV free-electron lasers are identified. A flatness as low as 4 nm r.m.s. on 3 × 3 mm beam splitters and 22 nm r.m.s. on 10 × 10 mm beam splitters has been obtained. The high-spatial-frequency surface roughness was about 0.7-1 nm r.m.s. The middle-spatial-frequency roughness was in the range 0.2-0.8 nm r.m.s. The reflection and transmission of the beam splitters were found to be very homogeneous, with a deviation of less than 2% across the full optical element.
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Affiliation(s)
- Ryszard Sobierajski
- FOM-Institute DIFFER, Edisonbaan 14, 3439 MN Nieuwegein, The Netherlands
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Rolf Antonie Loch
- FOM-Institute DIFFER, Edisonbaan 14, 3439 MN Nieuwegein, The Netherlands
| | | | - Eric Louis
- FOM-Institute DIFFER, Edisonbaan 14, 3439 MN Nieuwegein, The Netherlands
| | | | - Eric M. Gullikson
- Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Frank Siewert
- Helmholtz Zentrum Berlin/BESSY-II, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Andrzej Wawro
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland
| | - Fred Bijkerk
- FOM-Institute DIFFER, Edisonbaan 14, 3439 MN Nieuwegein, The Netherlands
- Mesa+ Institute for Nanotechnology at the University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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25
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Osaka T, Yabashi M, Sano Y, Tono K, Inubushi Y, Sato T, Matsuyama S, Ishikawa T, Yamauchi K. A Bragg beam splitter for hard x-ray free-electron lasers. OPTICS EXPRESS 2013; 21:2823-31. [PMID: 23481739 DOI: 10.1364/oe.21.002823] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We report a Bragg beam splitter developed for utilization of hard x-ray free-electron lasers. The splitter is based on an ultrathin silicon crystal operating in the symmetric Bragg geometry to provide high reflectivity and transmissivity simultaneously. We fabricated frame-shaped Si(511) and (110) crystals with thicknesses below 10 μm by a reactive dry etching method using atmospheric-pressure plasma. The thickness variation over an illuminated area is less than 300 nm peak-to-valley. High crystalline perfection was verified by topographic and diffractometric measurements. The crystal thickness was evaluated from the period of the Pendellösung beats measured with a highly monochromatic and collimated x-ray probe. The crystals provide two replica pulses with uniform wavefront [(<1/50)λ] and low spatial intensity variation (<5%). These Bragg beam splitters will play an important role in innovating XFEL applications.
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Affiliation(s)
- Taito Osaka
- Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1Yamada-oka, Suita, Osaka 565-0871, Japan.
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26
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Singer A, Sorgenfrei F, Mancuso AP, Gerasimova N, Yefanov OM, Gulden J, Gorniak T, Senkbeil T, Sakdinawat A, Liu Y, Attwood D, Dziarzhytski S, Mai DD, Treusch R, Weckert E, Salditt T, Rosenhahn A, Wurth W, Vartanyants IA. Spatial and temporal coherence properties of single free-electron laser pulses. OPTICS EXPRESS 2012; 20:17480-17495. [PMID: 23038301 DOI: 10.1364/oe.20.017480] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The experimental characterization of the spatial and temporal coherence properties of the free-electron laser in Hamburg (FLASH) at a wavelength of 8.0 nm is presented. Double pinhole diffraction patterns of single femtosecond pulses focused to a size of about 10×10 μm(2) were measured. A transverse coherence length of 6.2 ± 0.9 μm in the horizontal and 8.7 ± 1.0 μm in the vertical direction was determined from the most coherent pulses. Using a split and delay unit the coherence time of the pulses produced in the same operation conditions of FLASH was measured to be 1.75 ± 0.01 fs. From our experiment we estimated the degeneracy parameter of the FLASH beam to be on the order of 10(10) to 10(11), which exceeds the values of this parameter at any other source in the same energy range by many orders of magnitude.
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Affiliation(s)
- A Singer
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, D-22607 Hamburg, Germany
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27
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Ullrich J, Rudenko A, Moshammer R. Free-Electron Lasers: New Avenues in Molecular Physics and Photochemistry. Annu Rev Phys Chem 2012; 63:635-60. [DOI: 10.1146/annurev-physchem-032511-143720] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Joachim Ullrich
- Max Planck Institut für Kernphysik, D-69117 Heidelberg, Germany; ,
- Max Planck Advanced Study Group, Center for Free-Electron Laser Science, D-22607 Hamburg, Germany;
- Physikalisch-Technische Bundesanstalt, D-38116 Braunschweig, Germany
| | - Artem Rudenko
- Max Planck Institut für Kernphysik, D-69117 Heidelberg, Germany; ,
- Max Planck Advanced Study Group, Center for Free-Electron Laser Science, D-22607 Hamburg, Germany;
| | - Robert Moshammer
- Max Planck Institut für Kernphysik, D-69117 Heidelberg, Germany; ,
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28
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Ishikawa KL, Ueda K. Competition of resonant and nonresonant paths in resonance-enhanced two-photon single ionization of He by an ultrashort extreme-ultraviolet pulse. PHYSICAL REVIEW LETTERS 2012; 108:033003. [PMID: 22400736 DOI: 10.1103/physrevlett.108.033003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Indexed: 05/31/2023]
Abstract
We theoretically study the pulse-width dependence of the photoelectron angular distribution (PAD) from the resonance-enhanced two-photon single ionization of He by femtosecond (≲20 fs) extreme-ultraviolet pulses, based on the time-dependent perturbation theory and simulations with the full time-dependent Schrödinger equation. In particular, we focus on the competition between resonant and nonresonant ionization paths, which leads to the relative phase δ between the S and D wave packets distinct from the corresponding scattering phase shift difference. When the spectrally broadened pulse is resonant with an excited level, the competition varies with pulse width, and, therefore, δ and the PAD also change with it. On the other hand, when the Rydberg manifold is excited, δ and the PAD do not much vary with the pulse width, except for the very short-pulse regime.
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Affiliation(s)
- Kenichi L Ishikawa
- Photon Science Center, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656, Japan.
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29
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Gutt C, Wochner P, Fischer B, Conrad H, Castro-Colin M, Lee S, Lehmkühler F, Steinke I, Sprung M, Roseker W, Zhu D, Lemke H, Bogle S, Fuoss PH, Stephenson GB, Cammarata M, Fritz DM, Robert A, Grübel G. Single shot spatial and temporal coherence properties of the SLAC Linac Coherent Light Source in the hard x-ray regime. PHYSICAL REVIEW LETTERS 2012; 108:024801. [PMID: 22324689 DOI: 10.1103/physrevlett.108.024801] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Indexed: 05/31/2023]
Abstract
We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time τ(c)=(2.0±1.0) fc. The data suggest a mean x-ray pulse duration of (29±14) fs behind the monochromator for (100±14) fc electron pulses.
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Affiliation(s)
- C Gutt
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany.
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30
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Moshammer R, Pfeifer T, Rudenko A, Jiang YH, Foucar L, Kurka M, Kühnel KU, Schröter CD, Ullrich J, Herrwerth O, Kling MF, Liu XJ, Motomura K, Fukuzawa H, Yamada A, Ueda K, Ishikawa KL, Nagaya K, Iwayama H, Sugishima A, Mizoguchi Y, Yase S, Yao M, Saito N, Belkacem A, Nagasono M, Higashiya A, Yabashi M, Ishikawa T, Ohashi H, Kimura H, Togashi T. Second-order autocorrelation of XUV FEL pulses via time resolved two-photon single ionization of He. OPTICS EXPRESS 2011; 19:21698-21706. [PMID: 22109020 DOI: 10.1364/oe.19.021698] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Second-order autocorrelation spectra of XUV free-electron laser pulses from the Spring-8 Compact SASE Source (SCSS) have been recorded by time and momentum resolved detection of two-photon single ionization of He at 20.45 eV using a split-mirror delay-stage in combination with high-resolution recoil-ion momentum spectroscopy (COLTRIMS). From the autocorrelation trace we extract a coherence time of 8 ± 2 fs and a mean pulse duration of 28 ± 5 fs, much shorter than estimations based on electron bunch-length measurements. Simulations within the partial coherence model [Opt. Lett. 35, 3441 (2010)] are in agreement with experiment if a pulse-front tilt across the FEL beam diameter is taken into account that leads to a temporal shift of about 6 fs between both pulse replicas.
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Affiliation(s)
- R Moshammer
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
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31
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Altarelli M. From 3rd- to 4th-generation light sources: Free-electron lasers in the X-ray range. CRYSTALLOGR REP+ 2010. [DOI: 10.1134/s1063774510070072] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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32
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Pfeifer T, Jiang Y, Düsterer S, Moshammer R, Ullrich J. Partial-coherence method to model experimental free-electron laser pulse statistics. OPTICS LETTERS 2010; 35:3441-3443. [PMID: 20967093 DOI: 10.1364/ol.35.003441] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A general numerical approach is described that allows obtaining model sets of temporal pulse shapes of free-electron lasers (FELs) operating in the self-amplified spontaneous emission mode. Based on a random partial-coherence approach, sets of pulse shapes can be calculated that satisfy statistical criteria of FEL light predicted by established FEL theory. Importantly, the numerically retrieved sets of pulses reproduce the experimentally accessible FEL light characteristics as measured at the Free-electron LASer at Hamburg (FLASH), such as the average spectrum, single-shot spectral shape, and pulse duration. The high-precision agreement with the experimental average spectral shape, without further knowledge of FEL machine parameters, makes this approach a convenient tool for the analysis and theoretical modeling of nonlinear optical or pump-probe experiments with FEL light.
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Affiliation(s)
- Thomas Pfeifer
- Max-Planck Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany. tpfeifer@mpi‑hd.mpg.de
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33
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Sorgenfrei F, Schlotter WF, Beeck T, Nagasono M, Gieschen S, Meyer H, Föhlisch A, Beye M, Wurth W. The extreme ultraviolet split and femtosecond delay unit at the plane grating monochromator beamline PG2 at FLASH. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:043107. [PMID: 20441325 DOI: 10.1063/1.3374166] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
An extreme ultraviolet split and femtosecond delay unit based on grazing incidence Mach-Zehnder geometry has been designed and implemented on the plane grating monochromator beamline PG2 at FLASH, the Free Electron Laser at DESY. This device splits the FLASH radiation into two beams, which can independently be steered, filtered and temporally delayed between -5.1 and +5.1 ps with uncertainty in the temporal accuracy of 210 as. To demonstrate the performance of this device, we have performed longitudinal coherence studies of FLASH radiation as well as measured the pulse length by nonlinear two-photon double-ionization in helium.
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Affiliation(s)
- F Sorgenfrei
- Institut für Experimentalphysik and Centre for Free-Electron Laser Science, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
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34
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Fäustlin RR, Bornath T, Döppner T, Düsterer S, Förster E, Fortmann C, Glenzer SH, Göde S, Gregori G, Irsig R, Laarmann T, Lee HJ, Li B, Meiwes-Broer KH, Mithen J, Nagler B, Przystawik A, Redlin H, Redmer R, Reinholz H, Röpke G, Tavella F, Thiele R, Tiggesbäumker J, Toleikis S, Uschmann I, Vinko SM, Whitcher T, Zastrau U, Ziaja B, Tschentscher T. Observation of ultrafast nonequilibrium collective dynamics in warm dense hydrogen. PHYSICAL REVIEW LETTERS 2010; 104:125002. [PMID: 20366540 DOI: 10.1103/physrevlett.104.125002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Indexed: 05/29/2023]
Abstract
We investigate ultrafast (fs) electron dynamics in a liquid hydrogen sample, isochorically and volumetrically heated to a moderately coupled plasma state. Thomson scattering measurements using 91.8 eV photons from the free-electron laser in Hamburg (FLASH at DESY) show that the hydrogen plasma has been driven to a nonthermal state with an electron temperature of 13 eV and an ion temperature below 0.1 eV, while the free-electron density is 2.8x10{20} cm{-3}. For dense plasmas, our experimental data strongly support a nonequilibrium kinetics model that uses impact ionization cross sections based on classical free-electron collisions.
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35
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Siemer B, Hoger T, Rutkowski M, Treusch R, Zacharias H. Desorption of ionic species from ice/graphite by femtosecond XUV free-electron laser pulses. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:084013. [PMID: 21389389 DOI: 10.1088/0953-8984/22/8/084013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report results of laser desorption from water ice surfaces using XUV pulses from the free-electron laser in Hamburg (FLASH). This XUV to soft x-ray FEL provides femtosecond pulses at 20-200 eV photon energy with pulse energies up to 100 µJ. The interaction of this intense soft x-ray radiation with ice (H2O, D2O) adsorbed on highly oriented pyrolytic graphite (HOPG) yields the desorption of various ions, particularly H (+) (D (+) ), O (+) , O2 (+) and others. For H (+) and O (+) ions linear desorption yields are observed, while for O2 (+) a highly nonlinear desorption yield with n = (2.5 ± 0.2) is found. Kinetic energies of 1.8 eV, 559 meV and 390 meV for H (+) , O (+) , and O2 (+) , respectively, account for only a small part of the available excess energy.
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Affiliation(s)
- B Siemer
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm Klemm Strasse 10, 48149 Münster, Germany
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36
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Schlotter WF, Sorgenfrei F, Beeck T, Beye M, Gieschen S, Meyer H, Nagasono M, Föhlisch A, Wurth W. Longitudinal coherence measurements of an extreme-ultraviolet free-electron laser. OPTICS LETTERS 2010; 35:372-374. [PMID: 20125725 DOI: 10.1364/ol.35.000372] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have measured the average single-pulse longitudinal coherence characteristics of FLASH, a self amplified spontaneous emission free electron laser, at extreme UV wavelengths. Electric field autocorrelation measurements in the time domain were enabled by a wavefront division beam splitter applied to a tunable delay Mach-Zehnder interferometer. These data agree with the spectral bandwidth measurements made in the frequency domain. They exhibit two correlation time scales and the measured coherence curves have relevant implications for single-shot measurements.
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Affiliation(s)
- W F Schlotter
- Institute for Experimental Physics, University of Hamburg and Center for Free Electron Laser Science,22761 Hamburg, Germany.
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