144 results on '"Capotondi, Flavio"'
Search Results
2. The effect of echoes interference on phonon attenuation in a nanophononic membrane
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Hadi, Mohammad, Luo, Haoming, Pailhès, Stéphane, Tanguy, Anne, Gravouil, Anthony, Capotondi, Flavio, De Angelis, Dario, Fainozzi, Danny, Foglia, Laura, Mincigrucci, Riccardo, Paltanin, Ettore, Pedersoli, Emanuele, Pelli-Cresi, Jacopo S., Bencivenga, Filippo, and Giordano, Valentina M.
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- 2024
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3. Ultrafast demagnetization in bulk nickel induced by X-ray photons tuned to Ni M3 and L3 absorption edges
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Kapcia, Konrad J., Tkachenko, Victor, Capotondi, Flavio, Lichtenstein, Alexander, Molodtsov, Serguei, Piekarz, Przemysław, and Ziaja, Beata
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- 2024
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4. A versatile wide energy range spectrometer for soft X-ray FELs
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Principi, Emiliano, Svetina, Cristian, De Angelis, Dario, Fava, Claudio, Mincigrucci, Riccardo, Foglia, Laura, Simoncig, Alberto, Manfredda, Michele, Mahne, Nicola, Gobessi, Riccardo, Scarcia, Martin, Gessini, Alessandro, Bencivenga, Filippo, Capotondi, Flavio, Zangrando, Marco, and Masciovecchio, Claudio
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- 2024
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5. Ultrafast time-evolution of chiral Néel magnetic domain walls probed by circular dichroism in x-ray resonant magnetic scattering
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Léveillé, Cyril, Burgos-Parra, Erick, Sassi, Yanis, Ajejas, Fernando, Chardonnet, Valentin, Pedersoli, Emanuele, Capotondi, Flavio, De Ninno, Giovanni, Maccherozzi, Francesco, Dhesi, Sarnjeet, Burn, David M., van der Laan, Gerrit, Latcham, Oliver S., Shytov, Andrey V., Kruglyak, Volodymyr V., Jal, Emmanuelle, Cros, Vincent, Chauleau, Jean-Yves, Reyren, Nicolas, Viret, Michel, and Jaouen, Nicolas
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- 2022
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6. Separation of kinetic rate orders in extreme ultraviolet transient grating spectroscopy.
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Marroux, Hugo J B, Polishchuk, Serhii, Cannelli, Oliviero, Ingle, Rebecca A, Mancini, Giulia F, Bacellar, Camila, Puppin, Michele, Geneaux, Romain, Knopp, Gregor, Foglia, Laura, Pedersoli, Emanuele, Capotondi, Flavio, Nikolov, Ivaylo Petrov, Bencivenga, Filippo, Mincigrucci, Riccardo, Masciovecchio, Claudio, and Chergui, Majed
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SPECTROMETRY ,SPINEL ,ELECTRON-hole recombination ,COBALT oxides - Abstract
We present an extreme ultraviolet (EUV) transient grating (TG) experiment of the spinel Co
3 O4 compound using tuneable incident energies across the Co M2,3 -edge and a 395 nm probe pulse, detecting both the first and the second diffraction orders (SDOs). While the first diffraction order shows a monotonous behavior as a function of time, with a sharp response at t = 0, followed by a weak sub-picosecond component and a nearly constant signal thereafter, the time dependence of SDO varies dramatically with the incident energy as it is tuned across the Co M-edge, with the appearance of a component at t > 1 ps that grows with increasing energy. The results are rationalized in terms of the deviations of the initial grating from sinusoidal to non-sinusoidal, namely a flattening of the grating pattern, that introduces new Fourier components. These deviations are due to higher order, three-body terms in the population relaxation kinetics. The present results highlight the use of the SDO response in EUV TG as a tool to identify higher order terms in the population kinetics. [ABSTRACT FROM AUTHOR]- Published
- 2024
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7. Exploring the Fundamental Spatial Limits of Magnetic All-Optical Switching.
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Steinbach, Felix, Atxitia, Unai, Yao, Kelvin, Borchert, Martin, Engel, Dieter, Bencivenga, Filippo, Foglia, Laura, Mincigrucci, Riccardo, Pedersoli, Emanuele, De Angelis, Dario, Pancaldi, Matteo, Fainozzi, Danny, Pelli Cresi, Jacopo Stefano, Paltanin, Ettore, Capotondi, Flavio, Masciovecchio, Claudio, Eisebitt, Stefan, and von Korff Schmising, Clemens
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- 2024
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8. Temperature effects on the nanoscale thermoelastic response of a SiO2 membrane.
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Fainozzi, Danny, Caporaletti, Federico, Capotondi, Flavio, De Angelis, Dario, Duncan, Ryan A., Foglia, Laura, Martinelli, Alessandro, Mincigrucci, Riccardo, Nelson, Keith A., Pedersoli, Emanuele, Zanatta, Marco, Maznev, Alexei A., Monaco, Giulio, Bencivenga, Filippo, and Baldi, Giacomo
- Abstract
We crossed two femtosecond extreme ultraviolet (EUV) pulses on a 100 nm thick amorphous membrane of SiO
2 , generating transient gratings (TGs) of light intensity with 84 nm spatial periodicity. The EUV TG excitation gave rise to the efficient generation of Lamb waves (LWs) and of a temperature grating, whose dynamics was studied at two different initial sample temperatures, 50 and 300 K. The short penetration depth of the EUV excitation pulses turned into a strong non-uniformity in the actual temperature as a function of the depth from the sample surface. At the lowest temperature, the LW frequencies presented a sizable shift in time due to the thermal equilibration along the membrane thickness. The analysis of the EUV TG waveforms allowed us to determine the decay time of the thermal grating and the sound attenuation coefficient, both found in reasonable agreement with the literature. The results show how EUV TG can provide information of non-equilibrium thermoelastic dynamics in thin membranes transparent to optical radiation. [ABSTRACT FROM AUTHOR]- Published
- 2024
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9. A sub-100 nm thickness flat jet for extreme ultraviolet to soft X-ray absorption spectroscopy.
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De Angelis, Dario, Longetti, Luca, Bonano, Gabriele, Pelli Cresi, Jacopo Stefano, Foglia, Laura, Pancaldi, Matteo, Capotondi, Flavio, Pedersoli, Emanuele, Bencivenga, Filippo, Krstulovic, Marija, Menk, Ralf Hendrik, D'Addato, Sergio, Orlando, Stefano, de Simone, Monica, Ingle, Rebecca A., Bleiner, Davide, Coreno, Marcello, Principi, Emiliano, Chergui, Majed, and Masciovecchio, Claudio
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X-ray absorption ,SOFT X rays ,X-ray spectroscopy ,FREE electron lasers ,LIGHT elements ,SOLVENTS - Abstract
Experimental characterization of the structural, electronic and dynamic properties of dilute systems in aqueous solvents, such as nanoparticles, molecules and proteins, are nowadays an open challenge. X-ray absorption spectroscopy (XAS) is probably one of the most established approaches to this aim as it is element-specific. However, typical dilute systems of interest are often composed of light elements that require extreme-ultraviolet to soft X-ray photons. In this spectral regime, water and other solvents are rather opaque, thus demanding radical reduction of the solvent volume and removal of the liquid to minimize background absorption. Here, we present an experimental endstation designed to operate a liquid flat jet of sub-micrometre thickness in a vacuum environment compatible with extreme ultraviolet/soft XAS measurements in transmission geometry. The apparatus developed can be easily connected to synchrotron and free-electron-laser user-facility beamlines dedicated to XAS experiments. The conditions for stable generation and control of the liquid flat jet are analyzed and discussed. Preliminary soft XAS measurements on some test solutions are shown. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Author Correction: Faster chiral versus collinear magnetic order recovery after optical excitation revealed by femtosecond XUV scattering
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Kerber, Nico, Ksenzov, Dmitriy, Freimuth, Frank, Capotondi, Flavio, Pedersoli, Emanuele, Lopez-Quintas, Ignacio, Seng, Boris, Cramer, Joel, Litzius, Kai, Lacour, Daniel, Zabel, Hartmut, Mokrousov, Yuriy, Kläui, Mathias, and Gutt, Christian
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- 2021
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11. Effect of Auger recombination on transient optical properties in XUV and soft X-ray irradiated silicon nitride
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Tkachenko, Victor, Lipp, Vladimir, Büscher, Martin, Capotondi, Flavio, Höppner, Hauke, Medvedev, Nikita, Pedersoli, Emanuele, Prandolini, Mark J., Rossi, Giulio M., Tavella, Franz, Toleikis, Sven, Windeler, Matthew, Ziaja, Beata, and Teubner, Ulrich
- Published
- 2021
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12. Symmetry-resolved CO desorption and oxidation dynamics on O/Ru(0001) probed at the C K-edge by ultrafast x-ray spectroscopy.
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LaRue, Jerry, Liu, Boyang, Rodrigues, Gabriel L. S., Liu, Chang, Garrido Torres, Jose Antonio, Schreck, Simon, Diesen, Elias, Weston, Matthew, Ogasawara, Hirohito, Perakis, Fivos, Dell'Angela, Martina, Capotondi, Flavio, Ball, Devon, Carnahan, Conner, Zeri, Gary, Giannessi, Luca, Pedersoli, Emanuele, Naumenko, Denys, Amann, Peter, and Nikolov, Ivaylo
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X-ray spectroscopy ,OXIDATION of carbon monoxide ,TIME-resolved spectroscopy ,FEMTOSECOND pulses ,DESORPTION ,FEMTOSECOND lasers ,DIPOLE-dipole interactions ,OXIDATION states - Abstract
We report on carbon monoxide desorption and oxidation induced by 400 nm femtosecond laser excitation on the O/Ru(0001) surface probed by time-resolved x-ray absorption spectroscopy (TR-XAS) at the carbon K-edge. The experiments were performed under constant background pressures of CO (6 × 10
−8 Torr) and O2 (3 × 10−8 Torr). Under these conditions, we detect two transient CO species with narrow 2π* peaks, suggesting little 2π* interaction with the surface. Based on polarization measurements, we find that these two species have opposing orientations: (1) CO favoring a more perpendicular orientation and (2) CO favoring a more parallel orientation with respect to the surface. We also directly detect gas-phase CO2 using a mass spectrometer and observe weak signatures of bent adsorbed CO2 at slightly higher x-ray energies than the 2π* region. These results are compared to previously reported TR-XAS results at the O K-edge, where the CO background pressure was three times lower (2 × 10−8 Torr) while maintaining the same O2 pressure. At the lower CO pressure, in the CO 2π* region, we observed adsorbed CO and a distribution of OC–O bond lengths close to the CO oxidation transition state, with little indication of gas-like CO. The shift toward "gas-like" CO species may be explained by the higher CO exposure, which blocks O adsorption, decreasing O coverage and increasing CO coverage. These effects decrease the CO desorption barrier through dipole–dipole interaction while simultaneously increasing the CO oxidation barrier. [ABSTRACT FROM AUTHOR]- Published
- 2022
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13. Ultrafast demagnetization in bulk nickel induced by X-ray photons tuned to Ni M3 and L3 absorption edges.
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Kapcia, Konrad J., Tkachenko, Victor, Capotondi, Flavio, Lichtenstein, Alexander, Molodtsov, Serguei, Piekarz, Przemysław, and Ziaja, Beata
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DEMAGNETIZATION ,X-ray absorption ,X-rays ,NICKEL ,PHOTONS ,FERMI level - Abstract
Studies of light-induced demagnetization started with the experiment performed by Beaupaire et al. on Ni. Here, we present theoretical predictions for X-ray induced demagnetization of nickel, with X-ray photon energies tuned to its M 3 and L 3 absorption edges. We show that the specific feature in the density of states in the d-band of Ni, i.e., a sharp peak located just above the Fermi level, strongly influences the change of the predicted magnetic signal, making it stronger than in the previously studied case of X-ray demagnetized cobalt. It impacts also the value of Curie temperature for Ni. We believe that this finding will inspire dedicated experiments investigating magnetic processes in X-ray irradiated nickel and cobalt. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Coherent soft X-ray pulses from an echo-enabled harmonic generation free-electron laser
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Rebernik Ribič, Primož, Abrami, Alessandro, Badano, Laura, Bossi, Maurizio, Braun, Hans-Heinrich, Bruchon, Niky, Capotondi, Flavio, Castronovo, Davide, Cautero, Marco, Cinquegrana, Paolo, Coreno, Marcello, Couprie, Marie Emmanuelle, Cudin, Ivan, Boyanov Danailov, Miltcho, De Ninno, Giovanni, Demidovich, Alexander, Di Mitri, Simone, Diviacco, Bruno, Fawley, William M., Feng, Chao, Ferianis, Mario, Ferrari, Eugenio, Foglia, Laura, Frassetto, Fabio, Gaio, Giulio, Garzella, David, Ghaith, Amin, Giacuzzo, Fabio, Giannessi, Luca, Grattoni, Vanessa, Grulja, Sandi, Hemsing, Erik, Iazzourene, Fatma, Kurdi, Gabor, Lonza, Marco, Mahne, Nicola, Malvestuto, Marco, Manfredda, Michele, Masciovecchio, Claudio, Miotti, Paolo, Mirian, Najmeh S., Petrov Nikolov, Ivaylo, Penco, Giuseppe Maria, Penn, Gregory, Poletto, Luca, Pop, Mihai, Prat, Eduard, Principi, Emiliano, Raimondi, Lorenzo, Reiche, Sven, Roussel, Eléonore, Sauro, Roberto, Scafuri, Claudio, Sigalotti, Paolo, Spampinati, Simone, Spezzani, Carlo, Sturari, Luca, Svandrlik, Michele, Tanikawa, Takanori, Trovó, Mauro, Veronese, Marco, Vivoda, Davide, Xiang, Dao, Zaccaria, Maurizio, Zangrando, Dino, Zangrando, Marco, and Allaria, Enrico Massimiliano
- Published
- 2019
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15. Faster chiral versus collinear magnetic order recovery after optical excitation revealed by femtosecond XUV scattering
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Kerber, Nico, Ksenzov, Dmitriy, Freimuth, Frank, Capotondi, Flavio, Pedersoli, Emanuele, Lopez-Quintas, Ignacio, Seng, Boris, Cramer, Joel, Litzius, Kai, Lacour, Daniel, Zabel, Hartmut, Mokrousov, Yuriy, Kläui, Mathias, and Gutt, Christian
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- 2020
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16. Soft x-ray induced femtosecond solid-to-solid phase transition
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Tavella, Franz, Höppner, Hauke, Tkachenko, Victor, Medvedev, Nikita, Capotondi, Flavio, Golz, Torsten, Kai, Yun, Manfredda, Michele, Pedersoli, Emanuele, Prandolini, Mark J., Stojanovic, Nikola, Tanikawa, Takanori, Teubner, Ulrich, Toleikis, Sven, and Ziaja, Beata
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- 2017
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17. Publisher Correction: Seeded X-ray free-electron laser generating radiation with laser statistical properties
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Gorobtsov, Oleg Yu., Mercurio, Giuseppe, Capotondi, Flavio, Skopintsev, Petr, Lazarev, Sergey, Zaluzhnyy, Ivan A., Danailov, Miltcho B., Dell’Angela, Martina, Manfredda, Michele, Pedersoli, Emanuele, Giannessi, Luca, Kiskinova, Maya, Prince, Kevin C., Wurth, Wilfried, and Vartanyants, Ivan A.
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- 2019
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18. Evidence of extreme domain wall speeds under ultrafast optical excitation
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Jangid, Rahul, Hagström, Nanna Zhou, Madhavi, Meera, Rockwell, Kyle, Shaw, Justin M., Brock, Jeffrey A., Pancaldi, Matteo, De Angelis, Dario, Capotondi, Flavio, Pedersoli, Emanuele, Nembach, Hans T., Keller, Mark W., Bonetti, Stefano, Fullerton, Eric E., Iacocca, Ezio, Kukreja, Roopali, and Silva, Thomas J.
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,FOS: Physical sciences - Abstract
Time-resolved ultrafast EUV magnetic scattering was used to test a recent prediction of >10 km/s domain wall speeds by optically exciting a magnetic sample with a nanoscale labyrinthine domain pattern. Ultrafast distortion of the diffraction pattern was observed at markedly different timescales compared to the magnetization quenching. The diffraction pattern distortion shows a threshold-dependence with laser fluence, not seen for magnetization quenching, consistent with a picture of domain wall motion with pinning sites. Supported by simulations, we show that a speed of $\approx$ 66 km/s for highly curved domain walls can explain the experimental data. While our data agree with the prediction of extreme, non-equilibrium wall speeds locally, it differs from the details of the theory, suggesting that additional mechanisms are required to fully understand these effects., 5 pages, 4 figures; Supplemental Material: 9 pages, 9 figures
- Published
- 2023
19. Non-linear Harmonics of a Seeded FEL at the Water Window and Beyond
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Nikolov,Ivaylo, Manfredda,Michele, Stefano,Pelli Cresi, Masciovecchio,Claudio, Perosa,Giovanni, Pedersoli,Emanuele, Bencivenga,Filippo, Allaria,Enrico, Roesner,Benedikt, Dal Zilio,Simone, Vodungbo,Boris, Malvestuto,Marco, Luning,Jan, Giannessi,Luca, Hennes,Marcel, Sottocorona,Filippo, Kurdi,Gabor, Di Mitri,Simone, Spezzani,Carlo, Callegari,Carlo, Roussel,Eléonore, Capotondi,Flavio, Mincigrucci,Riccardo, Demidovich,Alexander, Sacchi,Maurizio, De Ninno,Giovanni, Rebernik Ribic,Primoz, Badano,Laura, Simoncig,Alberto, Zangrando,Marco, David,Christian, Bougiatioti,Panagiota, Penco,Giuseppe, Jal,Emmanuelle, Cinquegrana,Paolo, Spampinati,Simone, Trovo,Mauro, Foglia,Laura, Gaio,Giulio, Caretta,Antonio, Principi,Emiliano, Danailov,Miltcho, Brynes,Alexander, Chardonnet,Valentin, Gessini,Alessandro, and De Angelis,Dario
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seeded-fel - Seeded FEL ,Accelerator Physics - Abstract
The advent of free electron lasers (FELs) in the soft and hard X-ray spectral region has opened the possibility to probe electronic, magnetic and structural dynamics, in both diluted and condensed matter samples, with femtosecond time resolution. In particular, FELs strongly enhanced the capabilities of several analytical techniques, which took advantage of the high degree of transverse coherence provided. FELs based on the harmonic up-conversion of an external seed laser are characterised also by a high degree of longitudinal coherence, since electrons inherit the coherence properties of the seed. At the present state of the art, the shortest wavelength delivered to user experiments by an externally seeded FEL light source is about 4 nm. We show here that pulses with a high longitudinal degree of coherence (first and second order) covering the water window and with photon energy extending up to 790 eV can be generated by exploiting the so-called nonlinear harmonic regime, which allows generation of radiation at harmonics of the resonant FEL wavelength. Moreover, we report the results of two proof-of-principle experiments: one measuring the oxygen K-edge absorption in water ($\sim$ 530 eV), the other analysing the spin dynamics of Fe and Co through magnetic small angle x-ray scattering at their L-edges (707 eV and 780 eV)
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- 2023
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20. Future Upgrade Strategy of the FERMI Seeded FEL Facility
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Lonza,Marco, Nikolov,Ivaylo, Manfredda,Michele, Prince,Kevin, Masciovecchio,Claudio, Tanaka,Takashi, Giannessi,Luca, Ferianis,Mario, Bencivenga,Filippo, Allaria,Enrico, Shafqat,Nuaman, Scafuri,Claudio, Malvestuto,Marco, Diviacco,Bruno, Sigalotti,Paolo, Gelmetti,Federico, Delgiusto,Paolo, Sottocorona,Filippo, Fawley,William, Di Mitri,Simone, Kurdi,Gabor, Capotondi,Flavio, Callegari,Carlo, Spezzani,Carlo, Demidovich,Alexander, De Ninno,Giovanni, Rebernik Ribic,Primoz, Badano,Laura, Simoncig,Alberto, Castronovo,Davide, Zangrando,Marco, Penn,Gregory, Penco,Giuseppe, Visintini,Roberto, Cinquegrana,Paolo, Veronese,Marco, Spampinati,Simone, Trovo,Mauro, Coreno,Marcello, Gaio,Giulio, Principi,Emiliano, Danailov,Miltcho, Perosa,Giovanni, and Sturari,Luca
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seeded-fel - Seeded FEL ,Accelerator Physics - Abstract
FERMI is implementing a development plan to keep the facility in a world-leading position on the base of the requests coming from the user community and the advises from the Scientific Advisory Council and the Machine Advisory Committee. The ultimate goal of this plan consists in doubling the maximum photon energy available and in reducing the pulse duration below the characteristic lifetime of the atomic core levels in the source spectral range. An upgrade of FERMI aimed at reaching the oxygen K-edge requires a profound modification of the FEL configurations and of the main components of the machine, including the linac and the undulator lines. One of the most promising approaches for this upgrade is to implement the echo-enabled harmonic generation (EEHG) scheme, relying on two external lasers to precisely control the spectrotemporal properties of the FEL pulse. The conversion to EEHG of the first stage of the double-stage harmonic cascade presently in use on FEL-2, would allow to reach harmonics as high as 120, enabling to generate coherent pulses down to 2 nm. The main aspects of the upgrade strategy will be discussed in this contribution.
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- 2023
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21. SASE-FEL Stochastic Spectroscopy Investigation on XUV Absorption and Emission Dynamics in Silicon
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Capotondi,Flavio, Prince,Kevin, Pedersoli,Emanuele, Foglia,Laura, Mincigrucci,Riccardo, Fausti,Daniele, Klein,Yishay, Principi,Emiliano, Shwartz,Sharon, Svetina,Cristian, Razzoli,Elia, Vartaniants,Ivan, Pelli Cresi,Jacopo Stefano, and De Angelis,Dario
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sase-fel - SASE FEL ,Accelerator Physics - Abstract
High-resolution emission/absorption spectroscopy with picosecond time resolution appears to be strategic in fundamental matter physics investigation as well as in functional materials characterization. Such a method typically requires a pulsed radiation source and high energy resolution, along with a large data statistic. In this work we demonstrate the possibility to retrieve high resolution absorption and emission spectra with picosecond time resolution, by exploiting the stochastic nature of the wide-band self-amplified FEL radiation provided by FERMI. In this work we get advantage of the two spectrometers present on the TIMEX beamline to reconstruct a 2D emission/absorption spectrum of a Si sample. To do so, we applied the singular value decomposition on the single-pulse incoming and outgoing spectra; by applying Tikhonov regularization, we were able to obtain spectra with an energy resolution of few tens of meV. In addition, we performed a time resolved characterization of the Si L23-edge and Si emission line at 99.3 eV by pumping the Si sample with visible laser below damage threshold. The result of this measurement allow us to claim for a bond softening phenomenon on the picosecond time-scale.
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- 2023
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22. Electronic processes occurring during ultrafast demagnetization of cobalt triggered by x-ray photons tuned to the Co L 3 resonance
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Kapcia, Konrad, Tkachenko, Victor, Capotondi, Flavio, Lichtenstein, Alexander, Molodtsov, Serguei, Mueller, Leonard, Philippi-Kobs, Andre, Piekarz, Przemysław, and Ziaja, Beata
- Abstract
Physical review / B 107(9), 094402 (2023). doi:10.1103/PhysRevB.107.094402, Magnetization dynamics triggered by ultrashort laser pulses has been attracting significant attention, with a strong focus on the dynamics excited by visible/near-infrared pulses. Only recently has a strong magnetic response in solid materials induced by intense x-ray pulses from free-electron lasers been observed. The exact mechanisms that trigger the x-ray-induced demagnetization are not yet fully understood. They are the subject of ongoing experimental and theoretical investigations. Here, we present a theoretical analysis of electronic processes occurring during demagnetization of a Co multilayer system irradiated by x-ray pulses tuned to the $L_3$ absorption edge of cobalt. We show that, like in the case of x-ray-induced demagnetization at the $M$ edge of Co, electronic processes play a predominant role in the demagnetization until the pulse fluence does not exceed the structural damage threshold. The impact of electronic processes can explain reasonably well the available experimental data, without a need to introduce the mechanism of stimulated elastic forward scattering., Published by Inst., Woodbury, NY
- Published
- 2023
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23. AC/DC: The FERMI FEL Split and Delay Optical Device for Ultrafast X-Rays Science
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Pedersoli,Emanuele, Capotondi,Flavio, Pancaldi,Matteo, Manfredda,Michele, Raimondi,Lorenzo, Gaio,Giulio, Menk,Ralf Hendrik, Gerusina,Simone, Gobessi,Riccardo, Fava,Claudio, Simoncig,Alberto, Zangrando,Marco, Abrami,Alessandro, Mahne,Nicola, and De Angelis,Dario
- Subjects
photon-beamline-instrumentation-undulators - Photon beamline instrumentation & undulators ,Accelerator Physics - Abstract
Free-electron lasers (FELs) are currently the most advanced class of light sources, by virtue of their unique capability to lase high-brightness and ultrashort pulses characterized by wavelengths spanning the Extreme-Ultraviolet (EUV), the Soft (SXR) and Hard (HXR) X-Ray spectral domains, alongside with temporal duration lying in the femtosecond (fs) timescale [1]. Specifically, the advent of FELs light sources has recently allowed to perform, in a time-resolved fashion approach, both established spectroscopies, daily employed at synchrotron light sources, and novel non-linear optical methods, mostly combining FELs and laser pulses. Nonetheless, the next step to push the ultrafast X-Ray science standards is widely recognized to be linked to go beyond the current time-resolved schemes, so performing experiments engaging exclusively EUV, SXR and HXR pulses. Indeed, exciting (and probing) matter at its (or nearby) electronic resonance is largely speculated to be one of the key for discriminating and revealing the microscopic mechanisms hiding behind some of the most exotic phases of physical, chemical, and biological systems. Such a challenge calls the design of optical devices capable to both split and delay (in time) FELs pulses, without impacting on their coherence properties, and fully user-friendly in terms of preserving the perfect overlap of the resulting focal spots, even in the few microns spatial domain, a well-known trademark for focusing EUV, SXR and HXR pulses at FELs light sources [2]. At the seeded FERMI FEL (Trieste, Italy) this goal is committed by the novel optical device known as AC/DC, which stands for the Auto Correlator/Delay Creator. AC/DC is purposely designed to double the incoming FEL photon beam into two exact pulse replicas, splitting it by inserting a grazing incidence flat mirror, and further delaying in time, in a controlled way, one of the two pulses, with an intrinsic temporal resolution of approximately 360 attoseconds. A detailed description of AC/DC is highlighted here. Specifically, strong emphasis is dedicated to the opto-mechanical design and the laser-based feedback system, purposely designed and implemented to compensate in real-time any potential drift and pointing mismatch affecting the FEL optical trajectory, ascribable to both mechanical imperfections and residual paraxial errors appearing during a temporal delay scan [3]. [1] Bostedt C., Boutet S., Fritz D.M., Huang Z., Lee H.J., Lemke H.T., Robert A., Schlotter W.F., Turner J.J., Williams G.J., Linac Coherent Light Source: The first five years. Rev. Mod. Phys.88, 015007 (2016) [2] Manfredda M., Fava C., Gobessi R., Mahne N., Raimondi L., Simoncig A., Zangrando M., The evolution of KAOS, a multipurpose active optics system for EUV/Soft X-rays, Synchrotron Radiation News, 0, 0, (2022) DOI: 10.1080/08940886.2022.2066432 . [3] Simoncig A., Manfredda M., Gaio G., Mahne N., Raimondi M., Fava C., Gerusina S., Gobessi R., Abrami A., Capotondi F., De Angelis D., Menk R., Pancaldi M., Pedersoli E., Zangrando M., AC/DC: The FERMI FEL Split and Delay Optical Device for Ultrafast X-rays Science, Photonics, 9(5), 314, 2022
- Published
- 2023
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24. Seeded X-ray free-electron laser generating radiation with laser statistical properties
- Author
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Gorobtsov, Oleg Yu., Mercurio, Giuseppe, Capotondi, Flavio, Skopintsev, Petr, Lazarev, Sergey, Zaluzhnyy, Ivan A., Danailov, Miltcho B., Dell’Angela, Martina, Manfredda, Michele, Pedersoli, Emanuele, Giannessi, Luca, Kiskinova, Maya, Prince, Kevin C., Wurth, Wilfried, and Vartanyants, Ivan A.
- Published
- 2018
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25. Robust scenario for the generation of non-equilibrium topological fluctuation states
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Gerlinger, Kathinka, Liefferink, Rein, Schneider, Michael, Kern, Lisa-Marie, Klose, Christopher, Metternich, Daniel, Engel, Dieter, Capotondi, Flavio, De Angelis, Dario, Pancaldi, Matteo, Pedersoli, Emanuele, Büttner, Felix, Eisebitt, Stefan, Mentink, Johan H., and Pfau, Bastian
- Subjects
Condensed Matter - Materials Science ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences - Abstract
The recently discovered topological fluctuation state provides a fascinating new perspective on the ultrafast emergence of topology in condensed matter systems. However, rather little is known about the physics of this state and the origin of the topological fluctuations. Using time-resolved small-angle x-ray scattering, we observe that topological fluctuation states appear after laser excitation even if the final state does not host stable skyrmions. Simulations support these findings and reveal that the fluctuations originate from the competition between spontaneous nucleation and decay of skyrmions, consistent with Arrhenius-like activation over a potential barrier. Stable skyrmions can freeze out of such fluctuations when the effective temperature of the system relaxes faster than the decay time of the skyrmions. Our results reveal a robust scenario for the generation of topological fluctuation states, potentially enabling their study in a wide variety of magnetic systems.
- Published
- 2022
26. High energy-resolution transient ghost absorption spectroscopy
- Author
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Tripathi, Alok Kumar, Klein, Yishai, Strizhevsky, Edward, Capotondi, Flavio, De Angelis, Dario, Giannessi, Luca, Pancaldi, Matteo, Pedersoli, Emanuele, Prince, Kevin C., Sefi, Or, Kim, Young Yong, Vartanyants, Ivan A., and Shwartz, Sharon
- Subjects
Atomic Physics (physics.atom-ph) ,FOS: Physical sciences ,Optics (physics.optics) ,Physics - Optics ,Physics - Atomic Physics - Abstract
We demonstrate the measurement of ultrafast dynamics using ghost spectroscopy and a pump-probe approach with an optical pump and a short-wavelength radiation probe. The ghost spectroscopy approach is used to overcome the challenge of the strong intensity and spectrum fluctuations at free-electron lasers and to provide high -spectral resolution, which enables the measurement of small energy shifts in the absorption spectrum. We exploit the high resolution to explore the dynamics of the charge carrier excitations and relaxations and their impact on the photoinduced structural changes in silicon by measuring the variation of the absorption spectrum of a Si(100) membrane near the silicon L2,3 edge and the accompanying edge shifts in response to the optical illumination.
- Published
- 2022
27. Fermi 2.0 Future Upgrade Strategy
- Author
-
Giannessi, Luca, Allaria, Enrico, Badano, Laura, Bencivenga, Filippo, Callegari, Carlo, Capotondi, Flavio, Castronovo, Davide, Cinquegrana, Paolo, Coreno, Marcello, Danailov, Miltcho, De Ninno, Giovanni, Delgiusto, Paolo, Demidovich, Alexander, Di Mitri, Simone, Diviacco, Bruno, Fawley, William, Ferianis, Mario, Gaio, Giulio, Gelmetti, Federico, Kurdi, Gabor, Lonza, Marco, Malvestuto, Marco, Manfredda, Michele, Masciovecchio, Claudio, Nikolov, Ivaylo, Penco, Giuseppe, Penn, Gregory, Perosa, Giovanni, Prince, Kevin, Principi, Emiliano, Rebernik Ribič, Primoz, Scafuri, Claudio, Shafqat, Nuaman, Sigalotti, Paolo, Simoncig, Alberto, Sottocorona, Filippo, Spampinati, Simone, Spezzani, Carlo, Sturari, Luca, Tanaka, Takashi, Trovò, Mauro, Veronese, Marco, Visintini, Roberto, and Zangrando, Marco
- Subjects
MC2: Photon Sources and Electron Accelerators ,Accelerator Physics - Abstract
FERMI is studying a series of developments to keep the facility in a world-leading position on the base of the requests coming from the user community, the Scientific Advisory Council and the Machine Advisory Committee. The ultimate goal of the development plan consists in doubling the photon energy range and reducing the pulse duration below the characteristic lifetime of the atomic core levels located in the energy range of the source. One of the most promising approaches is the echo-enabled harmonic generation (EEHG) scheme, relying on two external lasers to precisely control the spectro-temporal properties of the FEL pulse. The implementation of EEHG in the double-stage harmonic cascade presently in use on FEL-2, would allow harmonics as high as 120 enabling to generate coherent pulses down to 2 nm starting from UV lasers. An upgrade of FERMI aimed at reaching the oxygen K-edge requires a profound modification of the FEL configurations and of the main components of the machine, including the linac and the undulator lines. The main aspects of the upgrade strategy will be discussed in this presentation., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand
- Published
- 2022
- Full Text
- View/download PDF
28. Electrochemical Preparation of Particles for X-Ray Free Electron Laser Based Diffractive Imaging
- Author
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Bozzini, Benedetto, Guerrieri, Marco, Capotondi, Flavio, Sgura, Ivonne, and Tondo, Elisabetta
- Published
- 2011
- Full Text
- View/download PDF
29. The COMIX polarimeter: a compact device for XUV polarization analysis.
- Author
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Pancaldi, Matteo, Strüber, Christian, Friedrich, Bertram, Pedersoli, Emanuele, De Angelis, Dario, Nikolov, Ivaylo P., Manfredda, Michele, Foglia, Laura, Yulin, Sergiy, Spezzani, Carlo, Sacchi, Maurizio, Eisebitt, Stefan, von Korff Schmising, Clemens, and Capotondi, Flavio
- Subjects
OPTICAL polarization ,MAGNETIC films ,VECTOR fields ,THIN films ,RADIATION ,POLARISCOPE ,TIME-resolved spectroscopy - Abstract
We report on the characterization of a novel extreme-ultraviolet polarimeter based on conical mirrors to simultaneously detect all the components of the electric field vector for extreme-ultraviolet radiation in the 45-90 eV energy range. The device has been characterized using a variable polarization source at the Elettra synchrotron, showing good performance in the ability to determine the radiation polarization. Furthermore, as a possible application of the device, Faraday spectroscopy and time-resolved experiments have been performed at the Fe M2,3-edge on an FeGd ferrimagnetic thin film using the FERMI freeelectron laser source. The instrument is shown to be able to detect the small angular variation induced by an optical external stimulus on the polarization state of the light after interaction with magnetic thin film, making the device an appealing tool for magnetization dynamics research. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
30. Chiral versus collinear magnetic order dynamics: faster chiral recovery after optical excitation revealed by femtosecond XUV scattering
- Author
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Kerber, Nico, Ksenzov, Dmitriy, Freimuth, Frank, Capotondi, Flavio, Pedersoli, Emanuele, Lopez-Quintas, Ignacio, Seng, Boris, Cramer, Joel, Litzius, Kai, Lacour, Daniel, Zabel, Hartmut, Mokrousov, Yuriy, Kläui, Mathias, Gutt, Christian, Elettra Sincrotrone Trieste, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut für Physik, Johannes Gutenberg-Universität Mainz, Department Physik, Universität Siegen, and Lacour, Daniel
- Subjects
[PHYS]Physics [physics] ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,[PHYS.COND] Physics [physics]/Condensed Matter [cond-mat] ,[PHYS] Physics [physics] - Abstract
While chiral spin structures stabilized by Dzyaloshinskii-Moriya interaction (DMI) are candidates as novel information carriers, their dynamics on the fs-ps timescale is little known. Since with the bulk Heisenberg exchange and the interfacial DMI two distinct exchange mechanisms are at play, the ultra-fast dynamics of the chiral order needs to be ascertained and compared to the dynamics of the conventional collinear order. Using an XUV free-electron laser we determine the fs-ps temporal evolution of the chiral order in domain walls in a magnetic thin film sample by an IR pump-X-ray magnetic scattering probe experiment. Upon demagnetisation we observe that the dichroic (CL-CR) signal from the chiral order in the domain walls recovers significantly faster than the (CL+CR) sum signal from the average collinear domain magnetisation. We explore possible explanations based on spin structure dynamics and reduced transversal magnetisation fluctuations inside the domain walls and find that the latter can explain the experimental data leading to distinctly different dynamics for collinear magnetic order and chiral magnetic order.
- Published
- 2020
31. Element- and enantiomer-selective visualization of ibuprofen dimer vibrations
- Author
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Mincigrucci, R., Rouxel, Jeremy, Rossi, Barbara, Principi, Emiliano, Bottari, Cettina, Catalini, Sara, Fainozzi, Danny, Foglia, Laura, Simoncig, Alberto, Matruglio, Alessia, Kurdi, Gabor, Capotondi, Flavio, Pedersoli, Emanuele, Perucchi, Andrea, Piccirilli, Federica, Gessini, Alessandro, Giarola, Marco, Mariotto, Gino, Mukamel, Shaul, Bencivenga, Filippo, Chergui, Majed, and Masciovecchio, Claudio
- Subjects
Physics::Atomic and Molecular Clusters ,Soft Condensed Matter (cond-mat.soft) ,FOS: Physical sciences ,Condensed Matter - Soft Condensed Matter - Abstract
In chemistry, biology and materials science, the ability to access interatomic interactions and their dynamical evolution has become possible with the advent of femtosecond lasers. In particular, the observation of vibrational wave packets via optical (UV-visible-IR) spectroscopies has been a major achievement as it can track the motion of nuclei within the system. However, optical spectroscopies only detect the effect of the interatomic vibrations on the global electronic surfaces. New tuneable, pulsed and polarized sources of short-wavelength radiation, such as X-Ray Free electron lasers, can overcome this limitation, allowing for chemical and, of primary importance in biochemistry, enantiomeric selectivity. This selectivity may be complemented by taking into account the chemical shifts of atoms belonging to different molecular moieties
- Published
- 2020
32. All-Optical Switching on the Nanometer Scale Excited and Probed with Femtosecond Extreme Ultraviolet Pulses.
- Author
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Yao, Kelvin, Steinbach, Felix, Borchert, Martin, Schick, Daniel, Engel, Dieter, Bencivenga, Filippo, Mincigrucci, Riccardo, Foglia, Laura, Pedersoli, Emanuele, De Angelis, Dario, Pancaldi, Matteo, Wehinger, Björn, Capotondi, Flavio, Masciovecchio, Claudio, Eisebitt, Stefan, and von Korff Schmising, Clemens
- Published
- 2022
- Full Text
- View/download PDF
33. AC/DC: The FERMI FEL Split and Delay Optical Device for Ultrafast X-ray Science.
- Author
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Simoncig, Alberto, Manfredda, Michele, Gaio, Giulio, Mahne, Nicola, Raimondi, Lorenzo, Fava, Claudio, Gerusina, Simone, Gobessi, Riccardo, Abrami, Alessandro, Capotondi, Flavio, De Angelis, Dario, Menk, Ralf Hendrik, Pancaldi, Matteo, Pedersoli, Emanuele, and Zangrando, Marco
- Subjects
OPTICAL devices ,DELAY lines ,FREE electron lasers ,X-rays ,GRAZING incidence ,PHYSICAL optics - Abstract
Free-electron lasers (FELs) are the most advanced class of light-sources, by virtue of their unique capability to lase high-brightness pulses characterized by wavelengths spanning the extreme-ultraviolet, the soft and hard X-ray spectral domains, as well as by temporal lengths lying in the femtosecond (fs) timescale. The next step to push the current standards in ultrafast X-ray science is strongly linked to the possibility of engineering and exploiting time-resolved experiments exclusively for FELs pulses, ideally having different colors tunable at specific electronic resonance of the chemical elements. At the seeded FERMI FEL (Trieste, Italy) this goal is committed to the optical device known as AC/DC, which stands for the auto correlator/delay creator. AC/DC is designed to double the incoming FEL pulse splitting the photon beam by inserting a grazing incidence flat mirror, thus preserving the spectral and temporal properties, and further delaying one of these two pulses in time. It can independently tune the FEL pulses fluence on the two optical paths by means of solid-state filters, too. Here, we present a detailed description about this optical device. Strong emphasis is dedicated to the AC/DC opto-mechanical design and to the laser-based feedback systems implemented to compensate for any mismatch affecting the FEL optical trajectory, ascribable to both mechanical imperfections and paraxial errors rising during a temporal delay scan. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. Single‐shot experiments at the soft X‐FEL FERMI using a back‐side‐illuminated scientific CMOS detector.
- Author
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Léveillé, Cyril, Desjardins, Kewin, Popescu, Horia, Vondungbo, Boris, Hennes, Marcel, Delaunay, Renaud, Jal, Emmanuelle, De Angelis, Dario, Pancaldi, Matteo, Pedersoli, Emanuele, Capotondi, Flavio, and Jaouen, Nicolas
- Subjects
OPTICAL detectors ,COMPLEMENTARY metal oxide semiconductors ,X-ray scattering ,FREE electron lasers ,SOFT X rays ,HARD X-rays ,DETECTORS - Abstract
The latest Complementary Metal Oxide Semiconductor (CMOS) 2D sensors now rival the performance of state‐of‐the‐art photon detectors for optical application, combining a high‐frame‐rate speed with a wide dynamic range. While the advent of high‐repetition‐rate hard X‐ray free‐electron lasers (FELs) has boosted the development of complex large‐area fast CCD detectors in the extreme ultraviolet (EUV) and soft X‐ray domains, scientists lacked such high‐performance 2D detectors, principally due to the very poor efficiency limited by the sensor processing. Recently, a new generation of large back‐side‐illuminated scientific CMOS sensors (CMOS‐BSI) has been developed and commercialized. One of these cost‐efficient and competitive sensors, the GSENSE400BSI, has been implemented and characterized, and the proof of concept has been carried out at a synchrotron or laser‐based X‐ray source. In this article, we explore the feasibility of single‐shot ultra‐fast experiments at FEL sources operating in the EUV/soft X‐ray regime with an AXIS‐SXR camera equipped with the GSENSE400BSI‐TVISB sensor. We illustrate the detector capabilities by performing a soft X‐ray magnetic scattering experiment at the DiProi end‐station of the FERMI FEL. These measurements show the possibility of integrating this camera for collecting single‐shot images at the 50 Hz operation mode of FERMI with a cropped image size of 700 × 700 pixels. The efficiency of the sensor at a working photon energy of 58 eV and the linearity over the large FEL intensity have been verified. Moreover, on‐the‐fly time‐resolved single‐shot X‐ray resonant magnetic scattering imaging from prototype Co/Pt multilayer films has been carried out with a time collection gain of 30 compared to the classical start‐and‐stop acquisition method performed with the conventional CCD‐BSI detector available at the end‐station. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
35. Spin susceptibility of two-dimensional hole gases in GaAs/AlGaAs heterostructures
- Author
-
Kumar, Mukesh, Mori, Giorgio, Capotondi, Flavio, Biasiol, Giorgio, and Sorba, Lucia
- Published
- 2005
- Full Text
- View/download PDF
36. Nanoscale Thermoelasticity in Silicon Nitride Membranes: Implications for Thermal Management.
- Author
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Milloch, Alessandra, Mincigrucci, Riccardo, Capotondi, Flavio, De Angelis, Dario, Foglia, Laura, Kurdi, Gabor, Naumenko, Denys, Pedersoli, Emanuele, Pelli-Cresi, Jacopo S., Simoncig, Alberto, Wehinger, Björn, Masciovecchio, Claudio, and Bencivenga, Filippo
- Abstract
The characterization of thermal and elastic properties at the nanometer length scale is fundamental for the implementation of materials in nanotechnology. Here, we show how four-wave mixing of extreme ultraviolet ultrashort pulses allows for high-precision measurements of nanoscale elasticity in thin suspended silicon nitride membranes through the generation and detection of Lamb waves at 10's of nm wavelengths. Our approach is contact-free and nondestructive, and it provides an estimate of both shear and longitudinal elastic moduli, without the need of nanopatterning. The data provide important information on nanoscale thermal transport and reveal a heat carrier behavior compatible with the diffusive regime. By controlling the fluence of the free-electron laser excitation pulses, we study the dependence of elastic moduli and the thermal relaxation rate on the sample temperature, which increases by hundreds of kelvins due to radiation absorption. At the same time, the experimental data allow us to estimate the characteristic time of phonon attenuation. The capability of determining this parameter, as well as the elastic moduli, at nanoscale wavelengths is a key aspect for the fundamental understanding of solids without translational invariance. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
37. First Lasing of a Free Electron Laser in the Soft X-Ray Spectral Range with Echo Enabled Harmonic Generation
- Author
-
Allaria, Enrico, Abrami, Alessandro, Badano, Laura, Bossi, Maurizio, Braun, Hans-Heinrich, Bruchon, Niky, Capotondi, Flavio, Castronovo, Davide, Cautero, Marco, Cinquegrana, Paolo, Coreno, Marcello, Couprie, Marie-Emmanuelle, Cudin, Ivan, Danailov, Miltcho, De Ninno, Giovanni, Demidovich, Alexander, Di Mitri, Simone, Diviacco, Bruno, Fawley, William, Feng, Chao, Ferianis, Mario, Ferrari, Eugenio, Foglia, Laura, Frassetto, Fabio, Gaio, Giulio, Garzella, David, Ghaith, Amin, Giacuzzo, Fabio, Giannessi, Luca, Grattoni, Vanessa, Grulja, Sandi, Hemsing, Erik, Iazzourene, Fatma, Kurdi, Gabor, Lonza, Marco, Mahne, Nicola, Malvestuto, Marco, Manfredda, Michele, Masciovecchio, Claudio, Miotti, Paolo, Mirian, Najmeh, Nikolov, Ivaylo, Penco, Giuseppe, Penn, Gregory, Poletto, Luca, Pop, Mihai, Prat, Eduard, Principi, Emiliano, Raimondi, Lorenzo, Rebernik Ribič, Primoz, Reiche, Sven, Roussel, Eléonore, Sauro, Roberto, Scafuri, Claudio, Sigalotti, Paolo, Spampinati, Simone, Spezzani, Carlo, Sturari, Luca, Svandrlik, Michele, Tanikawa, Takanori, Trovò, Mauro, Veronese, Marco, Vivoda, Davide, Xiang, Dao, Zaccaria, Maurizio, Zangrando, Dino, Zangrando, Marco, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), and Université de Lille-Centre National de la Recherche Scientifique (CNRS)
- Subjects
FEL ,electron ,free-electron laser ,experiment ,echo enabled harmonic generation ,[PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph] ,free-electron-laser ,Accelerator Physics ,First Lasing ,laser - Abstract
We report on the successful operation of a Free Electron Laser (FEL) in the Echo Enabled Harmonic Generation (EEHG) scheme at the FERMI facility at Sincrotrone Trieste. The experiment required a modification of the FEL-2 undulator line which, in normal operation, uses two stages of high-gain harmonic generation separated by a delay line. In addition to a new seed laser, the dispersion in the delay-line was increased, the second stage modulator changed and a new manipulator installed in the delay-line chicane hosting additional diagnostic components. With this modified setup we have demonstrated the first evidence of strong exponential gain in a free electron laser operated in EEHG mode at wavelengths as short as 5 nm., Proceedings of the 39th Free Electron Laser Conference, FEL2019, Hamburg, Germany
- Published
- 2019
38. Status and Perspectives of the FERMI FEL Facility (2019)
- Author
-
Giannessi, Luca, Allaria, Enrico, Badano, Laura, Bassanese, Silvano, Bencivenga, Filippo, Callegari, Carlo, Capotondi, Flavio, Castronovo, Davide, Cilento, Federico, Cinquegrana, Paolo, Coreno, Marcello, Cudin, Ivan, D'Auria, Gerardo, Danailov, Miltcho, De Monte, Raffaele, De Ninno, Giovanni, Delgiusto, Paolo, Demidovich, Alexander, Di Fraia, Michele, Di Mitri, Simone, Diviacco, Bruno, Fabris, Alessandro, Fabris, Riccardo, Fawley, William, Ferianis, Mario, Foglia, Laura, Furlan Radivo, Paolo, Gaio, Giulio, Gelmetti, Federico, Iazzourene, Fatma, Krecic, Stefano, Kurdi, Gabor, Lonza, Marco, Mahne, Nicola, Malvestuto, Marco, Manfredda, Michele, Masciovecchio, Claudio, Milloch, Massimo, Mincigrucci, Riccardo, Mirian, Najmeh, Nikolov, Ivaylo, O'Shea, Finn, Penco, Giuseppe, Perucchi, Andrea, Plekan, Oksana, Predonzani, Mauro, Prince, Kevin, Principi, Emiliano, Raimondi, Lorenzo, Rebernik Ribič, Primoz, Rossi, Fabio, Rumiz, Luca, Scafuri, Claudio, Serpico, Claudio, Shafqat, Nuaman, Sigalotti, Paolo, Simoncig, Alberto, Spampinati, Simone, Spezzani, Carlo, Svandrlik, Michele, Trovò, Mauro, Vascotto, Alessandro, Veronese, Marco, Visintini, Roberto, Zangrando, Dino, and Zangrando, Marco
- Subjects
Status of Projects and Facilities ,Accelerator Physics - Abstract
FERMI is the seeded Free Electron Laser (FEL) user facility at the Elettra laboratory in Trieste, operating in the VUV to EUV and soft X-rays spectral range; the radiation produced by the seeded FEL is characterized by wavelength stability, low temporal jitter and longitudinal coherence in the range 100-4 nm. During 2018 a dedicated experiment has shown the potential of the Echo Enabled Harmonic Generation (EEHG) scheme [1] to cover most of this spectral range with a single stage cascade [2]. Such a scheme, combined to an increment of the beam energy and of the accelerator performances, could extend the FERMI operating range toward the oxygen k-edge. With this perspective, we present the development plans under consideration for the next 3 to 5 years. These include an upgrade of the linac and of the existing FEL lines, consisting in the conversion of FEL-1 first, and FEL-2 successively, into EEHG seeded FELs., Proceedings of the 39th Free Electron Laser Conference, FEL2019, Hamburg, Germany
- Published
- 2019
- Full Text
- View/download PDF
39. Ultrafast Magnetisation Dynamics at the Low-Fluence Limit Supported by External Magnetic Fields
- Author
-
Riepp, Matthias, Bagschik, Kai, Capotondi, Flavio, Frömter, Robert, Golz, Torsten, Grübel, Gerhard, Kiskinova, Maya, Müller, Leonard, Naumenko, Denys, Oepen, Hans Peter, Pedersoli, Emanuele, Philippi-Kobs, André, Roseker, Wojciech, Rysov, Rustam, Stojanovic, Nikola, and Walther, Michael
- Subjects
Condensed Matter::Materials Science ,FEL Applications ,Physics::Atomic and Molecular Clusters ,Physics::Optics ,Accelerator Physics - Abstract
We report on ultrafast magnetisation dynamics in ferro-magnetic cobalt/platinum multilayers upon pumping by near and mid to far infrared radiation, utilizing sub-100 femtosecond free-electron laser pulses. The evolution of the excited magnetic state is studied on femtosecond timescales with nanometre spatial resolution and element selectivity, employing time-resolved magnetic small-angle X-ray scattering. The obtained results contribute to the ongoing discussion to what extent either coupling of the electromagnetic field or rather quasi-instantaneous heating of the electron-system is the driving force for phenomena like ultrafast demagnetization or all-optical helicity-dependent switching., Proceedings of the 39th Free Electron Laser Conference, FEL2019, Hamburg, Germany
- Published
- 2019
- Full Text
- View/download PDF
40. Status and Perspectives of the FERMI FEL Facility
- Author
-
Giannessi, Luca, Allaria, Enrico, Badano, Laura, Bencivenga, Filippo, Callegari, Carlo, Capotondi, Flavio, Cilento, Federico, Cinquegrana, Paolo, Coreno, Marcello, Cudin, Ivan, D'Auria, Gerardo, Danailov, Miltcho, De Monte, Raffaele, De Ninno, Giovanni, Delgiusto, Paolo, Demidovich, Alexander, Di Fraia, Michele, Di Mitri, Simone, Diviacco, Bruno, Fabris, Alessandro, Fabris, Riccardo, Fawley, William, Ferianis, Mario, Furlan Radivo, Paolo, Gaio, Giulio, Gauthier, David, Gelmetti, Federico, Iazzourene, Fatma, Krecic, Stefano, Lonza, Marco, Mahne, Nicola, Malvestuto, Marco, Masciovecchio, Claudio, Milloch, Massimo, Mirian, Najmeh, Parmigiani, Fulvio, Penco, Giuseppe, Perucchi, Andrea, Pivetta, Lorenzo, Plekan, Oksana, Predonzani, Mauro, Principi, Emiliano, Raimondi, Lorenzo, Rebernik Ribič, Primoz, Rossi, Fabio, Roussel, Eléonore, Rumiz, Luca, Scafuri, Claudio, Serpico, Claudio, Sigalotti, Paolo, Spampinati, Simone, Spezzani, Carlo, Svandrlik, Michele, Trovò, Mauro, Vascotto, Alessandro, Veronese, Marco, Visintini, Roberto, Zangrando, Dino, and Zangrando, Marco
- Subjects
New Lasing & Status of Projects ,Accelerator Physics - Abstract
FERMI is the seeded Free Electron Laser (FEL) user facility at the Elettra laboratory in Trieste, operating in the VUV to EUV and soft X-rays spectral range; the radiation produced by the seeded FEL is characterised by a number of desirable properties, such as wavelength stability, low temporal jitter and longitudinal coherence. In this paper, after an overview of the FELs performances, we will present the development plans under consideration for the next 3 to 5 years. These include an upgrade of the LINAC and of the existing FEL lines, the possibility to perform multi-pulse experiments in different configurations and an Echo Enabled Harmonic Generation experiment on FEL-2, the FEL line extending to 4 nm (310 eV)., Proceedings of the 38th Int. Free Electron Laser Conf., FEL2017, Santa Fe, NM, USA
- Published
- 2018
- Full Text
- View/download PDF
41. Simultaneous two-color snapshot view on ultrafast charge and spin dynamics in a Fe-Cu-Ni tri-layer.
- Author
-
Rösner, Benedikt, Vodungbo, Boris, Chardonnet, Valentin, Döring, Florian, Guzenko, Vitaliy A., Hennes, Marcel, Kleibert, Armin, Lebugle, Maxime, Lüning, Jan, Mahne, Nicola, Merhe, Aladine, Naumenko, Denys, Nikolov, Ivaylo P., Lopez-Quintas, Ignacio, Pedersoli, Emanuele, Ribič, Primož R., Savchenko, Tatiana, Watts, Benjamin, Zangrando, Marco, and Capotondi, Flavio
- Subjects
PICOSECOND pulses ,FREE electron lasers ,OPTICAL elements ,INFRARED lasers ,ELECTRONIC excitation ,DEGREES of freedom - Abstract
Ultrafast phenomena on a femtosecond timescale are commonly examined by pump-probe experiments. This implies multiple measurements, where the sample under investigation is pumped with a short light pulse and then probed with a second pulse at various time delays to follow its dynamics. Recently, the principle of streaking extreme ultraviolet (XUV) pulses in the temporal domain has enabled recording the dynamics of a system within a single pulse. However, separate pump-probe experiments at different absorption edges still lack a unified timing, when comparing the dynamics in complex systems. Here, we report on an experiment using a dedicated optical element and the two-color emission of the FERMI XUV free-electron laser to follow the charge and spin dynamics in composite materials at two distinct absorption edges, simultaneously. The sample, consisting of ferromagnetic Fe and Ni layers, separated by a Cu layer, is pumped by an infrared laser and probed by a two-color XUV pulse with photon energies tuned to the M-shell resonances of these two transition metals. The experimental geometry intrinsically avoids any timing uncertainty between the two elements and unambiguously reveals an approximately 100 fs delay of the magnetic response with respect to the electronic excitation for both Fe and Ni. This delay shows that the electronic and spin degrees of freedom are decoupled during the demagnetization process. We furthermore observe that the electronic dynamics of Ni and Fe show pronounced differences when probed at their resonance, while the demagnetization dynamics are similar. These observations underline the importance of simultaneous investigation of the temporal response of both charge and spin in multi-component materials. In a more general scenario, the experimental approach can be extended to continuous energy ranges, promising the development of jitter-free transient absorption spectroscopy in the XUV and soft X-ray regimes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
42. Pulse‐to‐pulse wavefront sensing at free‐electron lasers using ptychography.
- Author
-
Sala, Simone, Daurer, Benedikt J., Odstrcil, Michal, Capotondi, Flavio, Pedersoli, Emanuele, Hantke, Max F., Manfredda, Michele, Loh, N. Duane, Thibault, Pierre, and Maia, Filipe R. N. C.
- Subjects
FOCUS (Optics) ,LASERS ,FREE electron lasers ,X-ray lasers ,WAVEFRONT sensors - Abstract
The pressing need for knowledge of the detailed wavefront properties of ultra‐bright and ultra‐short pulses produced by free‐electron lasers has spurred the development of several complementary characterization approaches. Here a method based on ptychography is presented that can retrieve high‐resolution complex‐valued wavefunctions of individual pulses without strong constraints on the illumination or sample object used. The technique is demonstrated within experimental conditions suited for diffraction experiments and exploiting Kirkpatrick–Baez focusing optics. This lensless technique, applicable to many other short‐pulse instruments, can achieve diffraction‐limited resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
43. Time-resolved observation of transient precursor state of CO on Ru(0001) using carbon K-edge spectroscopy.
- Author
-
Wang, Hsin-Yi, Schreck, Simon, Weston, Matthew, Liu, Chang, Ogasawara, Hirohito, LaRue, Jerry, Perakis, Fivos, Dell'Angela, Martina, Capotondi, Flavio, Giannessi, Luca, Pedersoli, Emanuele, Naumenko, Denys, Nikolov, Ivaylo, Raimondi, Lorenzo, Spezzani, Carlo, Beye, Martin, Cavalca, Filippo, Liu, Boyang, Gladh, Jörgen, and Koroidov, Sergey
- Abstract
The transient dynamics of carbon monoxide (CO) molecules on a Ru(0001) surface following femtosecond optical laser pump excitation has been studied by monitoring changes in the unoccupied electronic structure using an ultrafast X-ray free-electron laser (FEL) probe. The particular symmetry of perpendicularly chemisorbed CO on the surface is exploited to investigate how the molecular orientation changes with time by varying the polarization of the FEL pulses. The time evolution of spectral features corresponding to the desorption precursor state was well distinguished due to the narrow line-width of the C K-edge in the X-ray absorption (XA) spectrum, illustrating that CO molecules in the precursor state rotated freely and resided on the surface for several picoseconds. Most of the CO molecules trapped in the precursor state ultimately cooled back down to the chemisorbed state, while we estimate that ∼14.5 ± 4.9% of the molecules in the precursor state desorbed into the gas phase. It was also observed that chemisorbed CO molecules diffused over the metal surface from on-top sites toward highly coordinated sites. In addition, a new "vibrationally hot precursor" state was identified in the polarization-dependent XA spectra. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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44. Splitting and delaying fully coherent FELs pulses for advancing ultrafast x-ray science: the AC/DC optical device at the FERMI FEL.
- Author
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Simoncig, Alberto, Manfredda, Michele, Gaio, Giulio, Mahne, Nicola, Raimondi, Lorenzo, Fava, Claudio, Gerusina, Simone, Gobessi, Riccardo, Abrami, Alessandro, Capotondi, Flavio, De Angelis, Dario, Menk, Ralf Hendrik, Pancaldi, Matteo, Pedersoli, Emanuele, and Zangrando, Marco
- Published
- 2023
- Full Text
- View/download PDF
45. Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering
- Author
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Ferrari, Eugenio, Spezzani, Carlo, Fortuna, Franck, Delaunay, Renaud, Vidal, Franck, Nikolov, Ivaylo, Cinquegrana, Paolo, Diviacco, Bruno, Gauthier, David, Penco, Giuseppe, Ribic, Primoz Rebernik, Roussel, Eleonore, Trovo, Marco, Moussy, Jean Baptiste, Pincelli, Tommaso, Lounis, Lounès, Manfredda, Michele, Pedersoli, Emanuele, Capotondi, Flavio, Svetina, Cristian, Mahne, Nicola, Zangrando, Marco, Raimondi, Lorenzo, Demidovich, Alexander, Giannessi, Luca, De Ninno, Giovanni, Danailov, Miltcho Boyanov, Allaria, Enrico, Sacchi, Maurizio, Elettra Sincrotrone Trieste, ELETTRA Sincrotrone Trieste, Dipartimento di Fisica ( DIPARTIMENTO DI FISICA ), Università degli studi di Trieste, Laboratoire de Physique des Solides ( LPS ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), Centre de Sciences Nucléaires et de Sciences de la Matière ( CSNSM ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Chimie Physique - Matière et Rayonnement ( LCPMR ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Croissance et propriétés de systèmes hybrides en couches minces ( INSP-E8 ), Institut des Nanosciences de Paris ( INSP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Service de physique de l'état condensé ( SPEC - UMR3680 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Dipartimento di Fisica (Milano), Università degli studi di Milano [Milano], École normale supérieure - Paris ( ENS Paris ), Graduate School of Nanotechnology, CNR - Istituto Officina dei Materiali ( IOM ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Italian National agency for new technologies, Energy and sustainable economic development [Frascati] ( ENEA ), Laboratory of Quantum Optics, University of Nova Gorica, Synchrotron SOLEIL ( SSOLEIL ), Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), CSNSM PS2, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Croissance et propriétés de systèmes hybrides en couches minces (INSP-E8), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, PSL Research University (PSL), CNR Istituto Officina dei Materiali (IOM), Consiglio Nazionale delle Ricerche [Roma] (CNR), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica [Trieste], Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Milano [Milano] (UNIMI), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL), Italian National agency for new technologies, Energy and sustainable economic development [Frascati] (ENEA), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph] ,Science ,General Physics and Astronomy ,Physics::Optics ,02 engineering and technology ,Electron ,01 natural sciences ,7. Clean energy ,Article ,General Biochemistry, Genetics and Molecular Biology ,law.invention ,Optics ,Optical physics ,law ,0103 physical sciences ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,Physics ,[PHYS]Physics [physics] ,Range (particle radiation) ,Multidisciplinary ,[ PHYS ] Physics [physics] ,business.industry ,Scattering ,Free-electron laser ,General Chemistry ,021001 nanoscience & nanotechnology ,Laser ,Physical sciences ,Applied physics ,Wavelength ,Extreme ultraviolet ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Optoelectronics ,Physics::Accelerator Physics ,0210 nano-technology ,business - Abstract
The advent of free-electron laser (FEL) sources delivering two synchronized pulses of different wavelengths (or colours) has made available a whole range of novel pump–probe experiments. This communication describes a major step forward using a new configuration of the FERMI FEL-seeded source to deliver two pulses with different wavelengths, each tunable independently over a broad spectral range with adjustable time delay. The FEL scheme makes use of two seed laser beams of different wavelengths and of a split radiator section to generate two extreme ultraviolet pulses from distinct portions of the same electron bunch. The tunability range of this new two-colour source meets the requirements of double-resonant FEL pump/FEL probe time-resolved studies. We demonstrate its performance in a proof-of-principle magnetic scattering experiment in Fe–Ni compounds, by tuning the FEL wavelengths to the Fe and Ni 3p resonances., Two-colour X-ray free electron laser is a powerful tool for pump–probe measurements, but currently constrained by limited tunability. Here, Ferrari et al. develop a configuration that allows tuning both the pump and the probe to specific electronic excitations, providing element selectivity.
- Published
- 2016
46. Direct Phasing of Finite Crystals Illuminated with a Free-Electron Laser
- Author
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Kirian, Richard A., Bean, Richard, Beyerlein, Kenneth, Barthelmess, Miriam, Yoon, Chun Hong, Wang, Fenglin, Capotondi, Flavio, Pedersoli, Emanuele, Barty, Anton, and Chapman, Henry N.
- Subjects
Physics ,QC1-999 ,ddc:530 - Abstract
It has been suggested that the extended intensity profiles surrounding Bragg reflections that arise when a series of finite crystals of varying size and shape are illuminated by the intense, coherent illumination of an x-ray free-electron laser may enable the crystal’s unit-cell electron density to be obtained ab initio via well-established iterative phasing algorithms. Such a technique could have a significant impact on the field of biological structure determination since it avoids the need for a priori information from similar known structures, multiple measurements near resonant atomic absorption energies, isomorphic derivative crystals, or atomic-resolution data. Here, we demonstrate this phasing technique on diffraction patterns recorded from artificial two-dimensional microcrystals using the seeded soft x-ray free-electron laser FERMI. We show that the technique is effective when the illuminating wavefront has nonuniform phase and amplitude, and when the diffraction intensities cannot be measured uniformly throughout reciprocal space because of a limited signal-to-noise ratio.
- Published
- 2015
47. The Fermi Seeded FEL Facility: Operational Experience and Future Perspectives
- Author
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Giannessi, Luca, Allaria, Enrico, Badano, Laura, Bencivenga, Filippo, Callegari, Carlo, Capotondi, Flavio, Castronovo, Davide, Cinquegrana, Paolo, Coreno, Marcello, Cucini, Riccardo, Cudin, Ivan, D'Auria, Gerardo, Danailov, Miltcho, De Monte, Raffaele, De Ninno, Giovanni, Delgiusto, Paolo, Demidovich, Alexander, Di Mitri, Simone, Diviacco, Bruno, Fabris, Alessandro, Fabris, Riccardo, Fawley, William, Ferianis, Mario, Ferrari, Eugenio, Finetti, Paola, Furlan Radivo, Paolo, Gaio, Giulio, Gauthier, David, Gelmetti, Federico, Iazzourene, Fatma, Kiskinova, Maya, Krecic, Stefano, Lonza, Marco, Mahne, Nicola, Manfredda, Michele, Masciovecchio, Claudio, Milloch, Massimo, Parmigiani, Fulvio, Pedersoli, Emanuele, Penco, Giuseppe, Pivetta, Lorenzo, Plekan, Oksana, Predonzani, Mauro, Prince, Kevin, Principi, Emiliano, Raimondi, Lorenzo, Rebernik Ribič, Primoz, Rossi, Fabio, Roussel, Eléonore, Rumiz, Luca, Scafuri, Claudio, Serpico, Claudio, Sigalotti, Paolo, Svandrlik, Michele, Svetina, Cristian, Trovò, Mauro, Vascotto, Alessandro, Veronese, Marco, Visintini, Roberto, Zangrando, Dino, and Zangrando, Marco
- Subjects
Status of Projects and Facilities ,Accelerator Physics - Abstract
FERMI is the seeded FEL user facility in Trieste, Italy, producing photons from the VUV to the soft X-rays with a high degree of coherence and spectral stability. Both FEL lines, FEL-1 and FEL-2, are available for users, down to the shortest wavelength of 4 nm. We report on the completion of the commissioning of the high energy FEL line, FEL-2, on the most recent progress obtained on FEL-1 and on the operational experience for users, in particular those requiring specific FEL configurations, such as two-colour experiments. We will also give a perspective on the improvements and upgrades which have been triggered based on our experience, aiming to maintain as well as to constantly improve the performance of the facility for our user community., Proceedings of the 37th International Free Electron Laser Conference, FEL2015, Daejeon, Republic of Korea
- Published
- 2015
- Full Text
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48. Kirkpatrick–Baez active optics system at FERMI: system performance analysis.
- Author
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Raimondi, Lorenzo, Manfredda, Michele, Mahne, Nicola, Cocco, Daniele, Capotondi, Flavio, Pedersoli, Emanuele, Kiskinova, Maya, and Zangrando, Marco
- Subjects
OPTICS ,FOCAL planes ,SYSTEM analysis ,FOCUS (Optics) ,WAVEFRONT sensors ,FREE electron lasers ,AUTOPSY - Abstract
FERMI is the first and only seeded EUV‐SXR free‐electron laser (FEL) facility available to users; it operates at Elettra – Sincrotrone Trieste (Italy) and it presents five operating endstations. Three of them, namely LDM (Low Density Matter), DiProI (Diffraction and Projection Imaging) and MagneDyn (Magneto‐Dynamical studies), use a Kirkpatrick–Baez (KB) active X‐ray optics system to focus the FEL pulses into the experimental chambers. The present work reports on the final results of the upgraded KB Active Optics Systems (KAOS), which have been mechanically modified in order to improve stability and repeatability with respect to the original design. The results have been obtained on both the FERMI FEL lines, FEL1 and FEL2, and are particularly relevant for the latter as it is the low‐wavelength line recently opened to users. After a thorough description of the new mechanical layout of the system and the aspects that have been improved after the refurbishment, a set of simulations of the optical performances are presented. The code used to simulate the behavior of KAOS is WISEr, a physical‐optics‐based tool, which is freely accessible, and integrated into the Oasys platform, that takes into account the specific surface metrology characterization of the beamline mirrors, including figure errors and microroughness power spectral density. The results of WISEr are then used as a reference for the actual optimization of the optical system. This procedure relies heavily on a wavefront sensor (WFS) mounted out of focus to optimize the refocusing mirrors alignment as well as their curvature bending (by minimization of the coefficients of the Zernike wavefront expansion). Moreover, the WFS data are used to reconstruct the focal spot parameters by means of a back‐propagation of the electric field. Finally, these results are compared with those obtained after the FEL ablation of a PMMA layer positioned on the focal plane, and analyzed ex situ in a post‐mortem fashion. The mechanically refurbished optical system and the multi‐technique alignment approach, aimed at optimizing the mirrors' curvature, pitch and roll angles, allowed a focal spot of 1.8 µm × 2.4 µm at 4.14 nm wavelength (FEL2) to be inferred, confirmed by the PMMA ablation imprints. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
49. Time-resolved ionization measurements with intense ultrashort XUV and X-ray free-electron laser pulses.
- Author
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Tkachenko, Victor, Büscher, Martin, Höppner, Hauke, Medvedev, Nikita, Lipp, Vladimir, Rossi, Giulio Maria, Capotondi, Flavio, Finetti, Paola, Pedersoli, Emanuele, Nikolov, Ivaylo, Danailov, Mitcho, Giannessi, Luca, Prandolini, Mark J., Toleikis, Sven, Mecseki, Katalin, Windeler, Matthew, Ziaja, Beata, Tavella, Franz, and Teubner, Ulrich
- Abstract
Modern free-electron lasers (FEL) operating in XUV (extreme ultraviolet) or X-ray range allow an access to novel research areas. An example is the ultrafast ionization of a solid by an intense femtosecond FEL pulse in XUV which consequently leads to a change of the complex index of refraction on an ultrashort timescale. The photoionization and subsequent impact ionization resulting in electronic and atomic dynamics are modeled with our hybrid code XTANT(X-ray thermal and non-thermal transitions) and a Monte Carlo code XCASCADE(X-ray-induced electron cascades). The simulations predict the temporal kinetics of FEL-induced electron cascades and thus yield temporally and spatially resolved information on the induced changes of the optical properties. In a series of experiments at FERMI and LCLS, single shot measurements with spatio-temporal encoding of the ionization process have been performed by a correlation of the FEL pump pulse with an optical femtosecond probe pulse. An excellent agreement between the experiment and the simulation has been found. We also show that such kind of experiments forms the basis for pulse duration and arrival time jitter monitoring as currently under development for XUV-FELs. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
50. Four-wave-mixing experiments and beyond: The TIMER/mini-TIMER setups at FERMI.
- Author
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Foglia, Laura, Bencivenga, Filippo, Mincigrucci, Riccardo, Simoncig, Alberto, Calvi, Andrea, Cucini, Riccardo, Principi, Emiliano, Zangrando, Marco, Mahne, Nicola, Manfredda, Michele, Raimondi, Lorenzo, Pedersoli, Emanuele, Capotondi, Flavio, Kiskinova, Maya, and Masciovecchio, Claudio
- Published
- 2017
- Full Text
- View/download PDF
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