Ago Marinelli is an assistant professor of Photon Science and Particle Physics and Astrophysics at the SLAC National Accelerator Laboratory. He received his PhD in physics from the University of California, Los Angeles in 2012 and moved to SLAC shortly after as a post-doctoral research associate. He was a Panofsky Fellow from 2015 to 2019 and joined the SLAC faculty in the fall of 2019.

He is currently the head of the free-electron laser physics department, as well as the co-lead of the free-electron laser R&D program at SLAC. His research is focused on the physics and applications of X-ray free-electron lasers as well as ultrafast light sources based on advanced particle accelerators.

Academic Appointments

Honors & Awards

  • Particle Accelerator Science and Technology Award, IEEE (2024)
  • Fellow of the American Physical Society, APS (2023)
  • Panofsky Fellowship, SLAC National Accelerator Laboratory (2015-2019)
  • Young Investigator Free-Electron Laser Prize, International Free-Electron Laser Conference (2015)
  • Outstanding Doctoral Thesis Research in Beam Physics Award, American Physical Society (2015)
  • Frank Sacherer Prize, European Physical Society (2014)

Professional Education

  • PhD, University of California, Los Angeles, Physics (2012)
  • Laurea Magistrale (M.S.), University of Rome, La Sapienza, Engineering Sciences (2007)
  • Laurea, University of Rome, La Sapienza, Electrical Engineering (2005)

Current Research and Scholarly Interests

X-ray free-electron lasers and applications.
Advanced particle accelerators.

2023-24 Courses

Stanford Advisees

All Publications

  • Attosecond coherent electron motion in Auger-Meitner decay. Science (New York, N.Y.) Li, S., Driver, T., Rosenberger, P., Champenois, E. G., Duris, J., Al-Haddad, A., Averbukh, V., Barnard, J. C., Berrah, N., Bostedt, C., Bucksbaum, P. H., Coffee, R. N., DiMauro, L. F., Fang, L., Garratt, D., Gatton, A., Guo, Z., Hartmann, G., Haxton, D., Helml, W., Huang, Z., LaForge, A. C., Kamalov, A., Knurr, J., Lin, M., Lutman, A. A., MacArthur, J. P., Marangos, J. P., Nantel, M., Natan, A., Obaid, R., O'Neal, J. T., Shivaram, N. H., Schori, A., Walter, P., Wang, A. L., Wolf, T. J., Zhang, Z., Kling, M. F., Marinelli, A., Cryan, J. P. 1800: eabj2096


    [Figure: see text].

    View details for DOI 10.1126/science.abj2096

    View details for PubMedID 34990213

  • Tunable isolated attosecond X-ray pulses with gigawatt peak power from a free-electron laser NATURE PHOTONICS Duris, J., Li, S., Driver, T., Champenois, E. G., MacArthur, J. P., Lutman, A. A., Zhang, Z., Rosenberger, P., Aldrich, J. W., Coffee, R., Coslovich, G., Decker, F., Glownia, J. M., Hartmann, G., Helml, W., Kamalov, A., Knurr, J., Krzywinski, J., Lin, M., Nantel, M., Natan, A., O'Neal, J., Shivaram, N., Walter, P., Wang, A., Welch, J. J., Wolf, T. A., Xu, J. Z., Kling, M. F., Bucksbaum, P. H., Zholents, A., Huang, Z., Cryan, J. P., Marinelli, A., Marangos, J. P. 2020; 14 (1): 30-+
  • Effect of the shot-to-shot variation on charge migration induced by sub-fs x-ray free-electron laser pulses PHYSICAL REVIEW RESEARCH Grell, G., Guo, Z., Driver, T., Decleva, P., Plesiat, E., Picon, A., Gonzalez-Vazquez, J., Walter, P., Marangos, J. P., Cryan, J. P., Marinelli, A., Palacios, A., Martin, F. 2023; 5 (2)
  • Observation of site-selective chemical bond changes via ultrafast chemical shifts. Nature communications Al-Haddad, A., Oberli, S., Gonzalez-Vazquez, J., Bucher, M., Doumy, G., Ho, P., Krzywinski, J., Lane, T. J., Lutman, A., Marinelli, A., Maxwell, T. J., Moeller, S., Pratt, S. T., Ray, D., Shepard, R., Southworth, S. H., Vazquez-Mayagoitia, A., Walter, P., Young, L., Picon, A., Bostedt, C. 2022; 13 (1): 7170


    The concomitant motion of electrons and nuclei on the femtosecond time scale marks the fate of chemical and biological processes. Here we demonstrate the ability to initiate and track the ultrafast electron rearrangement and chemical bond breaking site-specifically in real time for the carbon monoxide diatomic molecule. We employ a local resonant x-ray pump at the oxygen atom and probe the chemical shifts of the carbon core-electron binding energy. We observe charge redistribution accompanying core-excitation followed by Auger decay, eventually leading to dissociation and hole trapping at one site of the molecule. The presented technique is general in nature with sensitivity to chemical environment changes including transient electronic excited state dynamics. This work provides a route to investigate energy and charge transport processes in more complex systems by tracking selective chemical bond changes on their natural timescale.

    View details for DOI 10.1038/s41467-022-34670-2

    View details for PubMedID 36418902

  • The time-resolved atomic, molecular and optical science instrument at the Linac Coherent Light Source. Journal of synchrotron radiation Walter, P., Osipov, T., Lin, M. F., Cryan, J., Driver, T., Kamalov, A., Marinelli, A., Robinson, J., Seaberg, M. H., Wolf, T. J., Aldrich, J., Brown, N., Champenois, E. G., Cheng, X., Cocco, D., Conder, A., Curiel, I., Egger, A., Glownia, J. M., Heimann, P., Holmes, M., Johnson, T., Lee, L., Li, X., Moeller, S., Morton, D. S., Ng, M. L., Ninh, K., O'Neal, J. T., Obaid, R., Pai, A., Schlotter, W., Shepard, J., Shivaram, N., Stefan, P., Van, X., Wang, A. L., Wang, H., Yin, J., Yunus, S., Fritz, D., James, J., Castagna, J. C. 2022; 29 (Pt 4): 957-968


    The newly constructed time-resolved atomic, molecular and optical science instrument (TMO) is configured to take full advantage of both linear accelerators at SLAC National Accelerator Laboratory, the copper accelerator operating at a repetition rate of 120 Hz providing high per-pulse energy as well as the superconducting accelerator operating at a repetition rate of about 1 MHz providing high average intensity. Both accelerators power a soft X-ray free-electron laser with the new variable-gap undulator section. With this flexible light source, TMO supports many experimental techniques not previously available at LCLS and will have two X-ray beam focus spots in line. Thereby, TMO supports atomic, molecular and optical, strong-field and nonlinear science and will also host a designated new dynamic reaction microscope with a sub-micrometer X-ray focus spot. The flexible instrument design is optimized for studying ultrafast electronic and molecular phenomena and can take full advantage of the sub-femtosecond soft X-ray pulse generation program.

    View details for DOI 10.1107/S1600577522004283

    View details for PubMedID 35787561

  • Tunable x-ray free electron laser multi-pulses with nanosecond separation. Scientific reports Decker, F., Bane, K. L., Colocho, W., Gilevich, S., Marinelli, A., Sheppard, J. C., Turner, J. L., Turner, J. J., Vetter, S. L., Halavanau, A., Pellegrini, C., Lutman, A. A. 2022; 12 (1): 3253


    X-ray Free Electron Lasers provide femtosecond x-ray pulses with narrow bandwidth and unprecedented peak brightness. Special modes of operation have been developed to deliver double pulses for x-ray pump, x-ray probe experiments. However, the longest delay between the two pulses achieved with existing single bucket methods is less than 1picosecond, thus preventing the exploration of longer time-scale dynamics. We present a novel two-bucket scheme covering delays from 350picoseconds to hundreds of nanoseconds in discrete steps of 350picoseconds. Performance for each pulse can be similar to the one in a single pulse operation. The method has been experimentally tested with the Linac Coherent Light Source (LCLS-I) and the copper linac with LCLS-II hard x-ray undulators.

    View details for DOI 10.1038/s41598-022-06754-y

    View details for PubMedID 35228548

  • Characterization of single-shot attosecond pulses with angular streaking photoelectron spectra PHYSICAL REVIEW A Zhao, X., Li, S., Driver, T., Van-Hung Hoang, Anh-Thu Le, Cryan, J. P., Marinelli, A., Lin, C. D. 2022; 105 (1)
  • Temporal shaping of narrow-band picosecond pulses via noncolinear sum-frequency mixing of dispersion-controlled pulses PHYSICAL REVIEW ACCELERATORS AND BEAMS Lemons, R., Neveu, N., Duris, J., Marinelli, A., Durfee, C., Carbajo, S. 2022; 25 (1)
  • The development of attosecond XFELs for understanding ultrafast electron motion ADVANCES IN ATOMIC, MOLECULAR, AND OPTICAL PHYSICS, VOL. 71 Cryan, J. P., Driver, T., Duris, J., Guo, Z., Li, S., O'Neal, J. T., Marinelli, A., DiMauro, L. F., Perrin, H., Yelin, S. F. 2022; 71: 1-64
  • Controllable X-Ray Pulse Trains from Enhanced Self-Amplified Spontaneous Emission. Physical review letters Duris, J. P., MacArthur, J. P., Glownia, J. M., Li, S., Vetter, S., Miahnahri, A., Coffee, R., Hering, P., Fry, A., Welch, M. E., Lutman, A., Decker, F., Bohler, D., Mock, J. A., Xu, C., Gumerlock, K., May, J. E., Cedillos, A., Kraft, E., Carrasco, M. A., Smith, B. E., Chieffo, L. R., Xu, J. Z., Cryan, J. P., Huang, Z., Zholents, A., Marinelli, A. 2021; 126 (10): 104802


    We report the demonstration of optical compression of an electron beam and the production of controllable trains of femtosecond, soft x-ray pulses with the Linac Coherent Light Source (LCLS) free-electron laser (FEL). This is achieved by enhanced self-amplified spontaneous emission with a 2mum laser and a dechirper device. Optical compression was achieved by modulating the energy of an electron beam with the laser and then compressing with a chicane, resulting in high current spikes on the beam which we observe to lase. A dechirper was then used to selectively control the lasing region of the electron beam. Field autocorrelation measurements indicate a train of pulses, and we find that the number of pulses within the train can be controlled (from 1 to 5 pulses) by varying the dechirper position and undulator taper. These results are a step toward attosecond spectroscopy with x-ray FELs as well as future FEL schemes relying on optical compression of an electron beam.

    View details for DOI 10.1103/PhysRevLett.126.104802

    View details for PubMedID 33784160

  • Generation of Terawatt Attosecond Pulses from Relativistic Transition Radiation PHYSICAL REVIEW LETTERS Xu, X., Cesar, D. B., Corde, S., Yakimenko, V., Hogan, M. J., Joshi, C., Marinelli, A., Mori, W. B. 2021; 126 (9): 094801


    When a femtosecond duration and hundreds of kiloampere peak current electron beam traverses the vacuum and high-density plasma interface, a new process, that we call relativistic transition radiation (RTR), generates an intense ∼100 as pulse containing ∼1 terawatt power of coherent vacuum ultraviolet (VUV) radiation accompanied by several smaller femtosecond duration satellite pulses. This pulse inherits the radial polarization of the incident beam field and has a ring intensity distribution. This RTR is emitted when the beam density is comparable to the plasma density and the spot size much larger than the plasma skin depth. Physically, it arises from the return current or backward relativistic motion of electrons starting just inside the plasma that Doppler up shifts the emitted photons. The number of RTR pulses is determined by the number of groups of plasma electrons that originate at different depths within the first plasma wake period and emit coherently before phase mixing.

    View details for DOI 10.1103/PhysRevLett.126.094801

    View details for Web of Science ID 000627616700005

    View details for PubMedID 33750158

  • Time-resolved pump-probe spectroscopy with spectral domain ghost imaging. Faraday discussions Li, S., Driver, T., Alexander, O., Cooper, B., Garratt, D., Marinelli, A., Cryan, J. P., Marangos, J. P. 2021


    An atomic-level picture of molecular and bulk processes, such as chemical bonding and charge transfer, necessitates an understanding of the dynamical evolution of these systems. On the ultrafast timescales associated with nuclear and electronic motion, the temporal behaviour of a system is often interrogated in a 'pump-probe' scheme. Here, an initial 'pump' pulse triggers dynamics through photoexcitation, and after a carefully controlled delay a 'probe' pulse initiates projection of the instantaneous state of the evolving system onto an informative measurable quantity, such as electron binding energy. In this paper, we apply spectral ghost imaging to a pump-probe time-resolved experiment at an X-ray free-electron laser (XFEL) facility, where the observable is spectral absorption in the X-ray regime. By exploiting the correlation present in the shot-to-shot fluctuations in the incoming X-ray pulses and measured electron kinetic energies, we show that spectral ghost imaging can be applied to time-resolved pump-probe measurements. In the experiment presented, interpretation of the measurement is simplified because spectral ghost imaging separates the overlapping contributions to the photoelectron spectrum from the pump and probe pulse.

    View details for DOI 10.1039/d0fd00122h

    View details for PubMedID 33625412

  • Inner Valence Hole Migration in Isopropanol Alexander, O., Barillot, T., Cooper, B., Driver, T., Garratt, D., Li, S., Marinelli, A., Cryan, J. P., Marangos, J. P., LR25 Collaboration, IEEE IEEE. 2021
  • Electronic Population Transfer via Impulsive Stimulated X-Ray Raman Scattering with Attosecond Soft-X-Ray Pulses. Physical review letters O'Neal, J. T., Champenois, E. G., Oberli, S., Obaid, R., Al-Haddad, A., Barnard, J., Berrah, N., Coffee, R., Duris, J., Galinis, G., Garratt, D., Glownia, J. M., Haxton, D., Ho, P., Li, S., Li, X., MacArthur, J., Marangos, J. P., Natan, A., Shivaram, N., Slaughter, D. S., Walter, P., Wandel, S., Young, L., Bostedt, C., Bucksbaum, P. H., Picón, A., Marinelli, A., Cryan, J. P. 2020; 125 (7): 073203


    Free-electron lasers provide a source of x-ray pulses short enough and intense enough to drive nonlinearities in molecular systems. Impulsive interactions driven by these x-ray pulses provide a way to create and probe valence electron motions with high temporal and spatial resolution. Observing these electronic motions is crucial to understand the role of electronic coherence in chemical processes. A simple nonlinear technique for probing electronic motion, impulsive stimulated x-ray Raman scattering (ISXRS), involves a single impulsive interaction to produce a coherent superposition of electronic states. We demonstrate electronic population transfer via ISXRS using broad bandwidth (5.5 eV full width at half maximum) attosecond x-ray pulses produced by the Linac Coherent Light Source. The impulsive excitation is resonantly enhanced by the oxygen 1s→2π^{*} resonance of nitric oxide (NO), and excited state neutral molecules are probed with a time-delayed UV laser pulse.

    View details for DOI 10.1103/PhysRevLett.125.073203

    View details for PubMedID 32857563

  • Electronic Population Transfer via Impulsive Stimulated X-Ray Raman Scattering with Attosecond Soft-X-Ray Pulses PHYSICAL REVIEW LETTERS O'Neal, J. T., Champenois, E. G., Oberli, S., Obaid, R., Al-Haddad, A., Barnard, J., Berrah, N., Coffee, R., Duris, J., Galinis, G., Garratt, D., Glownia, J. M., Haxton, D., Ho, P., Li, S., Li, X., MacArthur, J., Marangos, J. P., Natan, A., Shivaram, N., Slaughter, D. S., Walter, P., Wandel, S., Young, L., Bostedt, C., Bucksbaum, P. H., Picon, A., Marinelli, A., Cryan, J. P. 2020; 125 (7)
  • Observation of Seeded Mn K beta Stimulated X-Ray Emission Using Two-Color X-Ray Free-Electron Laser Pulses PHYSICAL REVIEW LETTERS Kroll, T., Weninger, C., Fuller, F. D., Guetg, M. W., Benediktovitch, A., Zhang, Y., Marinelli, A., Alonso-Mori, R., Aquila, A., Liang, M., Koglin, J. E., Koralek, J., Sokaras, D., Zhu, D., Kern, J., Yano, J., Yachandra, V. K., Rohringer, N., Lutman, A., Bergmann, U. 2020; 125 (3)
  • Observation of Seeded Mn Kβ Stimulated X-Ray Emission Using Two-Color X-Ray Free-Electron Laser Pulses. Physical review letters Kroll, T., Weninger, C., Fuller, F. D., Guetg, M. W., Benediktovitch, A., Zhang, Y., Marinelli, A., Alonso-Mori, R., Aquila, A., Liang, M., Koglin, J. E., Koralek, J., Sokaras, D., Zhu, D., Kern, J., Yano, J., Yachandra, V. K., Rohringer, N., Lutman, A., Bergmann, U. 2020; 125 (3): 037404


    Kβ x-ray emission spectroscopy is a powerful probe for electronic structure analysis of 3d transition metal systems and their ultrafast dynamics. Selectively enhancing specific spectral regions would increase this sensitivity and provide fundamentally new insights. Recently we reported the observation and analysis of Kα amplified spontaneous x-ray emission from Mn solutions using an x-ray free-electron laser to create the 1s core-hole population inversion [Kroll et al., Phys. Rev. Lett. 120, 133203 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.133203]. To apply this new approach to the chemically more sensitive but much weaker Kβ x-ray emission lines requires a mechanism to outcompete the dominant amplification of the Kα emission. Here we report the observation of seeded amplified Kβ x-ray emission from a NaMnO_{4} solution using two colors of x-ray free-electron laser pulses, one to create the 1s core-hole population inversion and the other to seed the amplified Kβ emission. Comparing the observed seeded amplified Kβ emission signal with that from conventional Kβ emission into the same solid angle, we obtain a signal enhancement of more than 10^{5}. Our findings are the first important step of enhancing and controlling the emission of selected final states of the Kβ spectrum with applications in chemical and materials science.

    View details for DOI 10.1103/PhysRevLett.125.037404

    View details for PubMedID 32745427

  • Structural dynamics in proteins induced by and probed with X-ray free-electron laser pulses. Nature communications Nass, K., Gorel, A., Abdullah, M. M., V Martin, A., Kloos, M., Marinelli, A., Aquila, A., Barends, T. R., Decker, F., Bruce Doak, R., Foucar, L., Hartmann, E., Hilpert, M., Hunter, M. S., Jurek, Z., Koglin, J. E., Kozlov, A., Lutman, A. A., Kovacs, G. N., Roome, C. M., Shoeman, R. L., Santra, R., Quiney, H. M., Ziaja, B., Boutet, S., Schlichting, I. 2020; 11 (1): 1814


    X-ray free-electron lasers (XFELs) enable crystallographic structure determination beyond the limitations imposed upon synchrotron measurements by radiation damage. The need for very short XFEL pulses is relieved through gating of Bragg diffraction by loss of crystalline order as damage progresses, but not if ionization events are spatially non-uniform due to underlying elemental distributions, as in biological samples. Indeed, correlated movements of iron and sulfur ions were observed in XFEL-irradiated ferredoxin microcrystals using unusually long pulses of 80fs. Here, we report a femtosecond time-resolved X-ray pump/X-ray probe experiment on protein nanocrystals. We observe changes in the protein backbone and aromatic residues as well as disulfide bridges. Simulations show that the latter's correlated structural dynamics are much slower than expected for the predicted high atomic charge states due to significant impact of ion caging and plasma electron screening. This indicates that dense-environment effects can strongly affect local radiation damage-induced structural dynamics.

    View details for DOI 10.1038/s41467-020-15610-4

    View details for PubMedID 32286284

  • Simulation analysis and optimization of fresh-slice multistage free-electron lasers PHYSICAL REVIEW ACCELERATORS AND BEAMS Guo, T., Guetg, M. W., Ding, Y., Marinelli, A., Wu, J., Huang, Z., Lutman, A. A. 2020; 23 (3)
  • Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy. Physical chemistry chemical physics : PCCP Driver, T., Li, S., Champenois, E. G., Duris, J., Ratner, D., Lane, T. J., Rosenberger, P., Al-Haddad, A., Averbukh, V., Barnard, T., Berrah, N., Bostedt, C., Bucksbaum, P. H., Coffee, R., DiMauro, L. F., Fang, L., Garratt, D., Gatton, A., Guo, Z., Hartmann, G., Haxton, D., Helml, W., Huang, Z., LaForge, A., Kamalov, A., Kling, M. F., Knurr, J., Lin, M., Lutman, A. A., MacArthur, J. P., Marangos, J. P., Nantel, M., Natan, A., Obaid, R., O'Neal, J. T., Shivaram, N. H., Schori, A., Walter, P., Li Wang, A., Wolf, T. J., Marinelli, A., Cryan, J. P. 2019


    The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray transient absorption spectroscopy, where the X-ray absorption spectrum is measured by scanning the central photon energy and recording the resultant photoproducts. The spectral bandwidth inherent to attosecond pulses is wide compared to the resonant features typically probed, which generally precludes the application of this technique in the attosecond regime. In this paper we propose and demonstrate a new technique to conduct transient absorption spectroscopy with broad bandwidth attosecond pulses with the aid of ghost imaging, recovering sub-bandwidth resolution in photoproduct-based absorption measurements.

    View details for DOI 10.1039/c9cp03951a

    View details for PubMedID 31793561

  • Phase-Stable Self-Modulation of an Electron Beam in a Magnetic Wiggler. Physical review letters MacArthur, J. P., Duris, J., Zhang, Z., Lutman, A., Zholents, A., Xu, X., Huang, Z., Marinelli, A. 2019; 123 (21): 214801


    Electron beams with a sinusoidal energy modulation have the potential to emit subfemtosecond x-ray pulses in a free-electron laser. An energy modulation can be generated by overlapping a powerful infrared laser with an electron beam in a magnetic wiggler. We report on a new infrared source for this modulation, coherent radiation from the electron beam itself. In this self-modulation process, the current spike on the tail of the electron beam radiates coherently at the resonant wavelength of the wiggler, producing a six-period carrier-envelope-phase (CEP)-stable infrared field with gigawatt power. This field creates a few MeV, phase-stable modulation in the electron-beam core. The modulated electron beam is immediately useful for generating subfemtosecond x-ray pulses at any machine repetition rate, and the CEP-stable infrared field may find application as an experimental pump or timing diagnostic.

    View details for DOI 10.1103/PhysRevLett.123.214801

    View details for PubMedID 31809147

  • Development of ultrafast capabilities for X-ray free-electron lasers at the linac coherent light source. Philosophical transactions. Series A, Mathematical, physical, and engineering sciences Coffee, R. N., Cryan, J. P., Duris, J., Helml, W., Li, S., Marinelli, A. 2019; 377 (2145): 20180386


    The ability to produce ultrashort, high-brightness X-ray pulses is revolutionizing the field of ultrafast X-ray spectroscopy. Free-electron laser (FEL) facilities are driving this revolution, but unique aspects of the FEL process make the required characterization and use of the pulses challenging. In this paper, we describe a number of developments in the generation of ultrashort X-ray FEL pulses, and the concomitant progress in the experimental capabilities necessary for their characterization and use at the Linac Coherent Light Source. This includes the development of sub-femtosecond hard and soft X-ray pulses, along with ultrafast characterization techniques for these pulses. We also describe improved techniques for optical cross-correlation as needed to address the persistent challenge of external optical laser synchronization with these ultrashort X-ray pulses. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.

    View details for PubMedID 30929632

  • High-Power Femtosecond Soft X Rays from Fresh-Slice Multistage Free-Electron Lasers PHYSICAL REVIEW LETTERS Lutman, A. A., Guetg, M. W., Maxwell, T. J., MacArthur, J. P., Ding, Y., Emma, C., Krzywinski, J., Marinelli, A., Huang, Z. 2018; 120 (26): 264801


    We demonstrate a novel multistage amplification scheme for self-amplified spontaneous-emission free electron lasers for the production of few femtosecond pulses with very high power in the soft x-ray regime. The scheme uses the fresh-slice technique to produce an x-ray pulse on the bunch tail, subsequently amplified in downstream undulator sections by fresh electrons. With three-stages amplification, x-ray pulses with an energy of hundreds of microjoules are produced in few femtoseconds. For single-spike spectra x-ray pulses the pulse power is increased more than an order of magnitude compared to other techniques in the same wavelength range.

    View details for DOI 10.1103/PhysRevLett.120.264801

    View details for Web of Science ID 000436558800005

    View details for PubMedID 30004769

  • Stimulated X-Ray Emission Spectroscopy in Transition Metal Complexes PHYSICAL REVIEW LETTERS Kroll, T., Weninger, C., Alonso-Mori, R., Sokaras, D., Zhu, D., Mercadier, L., Majety, V. P., Marinelli, A., Lutman, A., Guetg, M. W., Decker, F., Boutet, S., Aquila, A., Koglin, J., Koralek, J., DePonte, D. P., Kern, J., Fuller, F. D., Pastor, E., Fransson, T., Zhang, Y., Yano, J., Yachandra, V. K., Rohringer, N., Bergmann, U. 2018; 120 (13): 133203


    We report the observation and analysis of the gain curve of amplified Kα x-ray emission from solutions of Mn(II) and Mn(VII) complexes using an x-ray free electron laser to create the 1s core-hole population inversion. We find spectra at amplification levels extending over 4 orders of magnitude until saturation. We observe bandwidths below the Mn 1s core-hole lifetime broadening in the onset of the stimulated emission. In the exponential amplification regime the resolution corrected spectral width of ∼1.7  eV FWHM is constant over 3 orders of magnitude, pointing to the buildup of transform limited pulses of ∼1  fs duration. Driving the amplification into saturation leads to broadening and a shift of the line. Importantly, the chemical sensitivity of the stimulated x-ray emission to the Mn oxidation state is preserved at power densities of ∼10^{20}  W/cm^{2} for the incoming x-ray pulses. Differences in signal sensitivity and spectral information compared to conventional (spontaneous) x-ray emission spectroscopy are discussed. Our findings build a baseline for nonlinear x-ray spectroscopy for a wide range of transition metal complexes in inorganic chemistry, catalysis, and materials science.

    View details for DOI 10.1103/PhysRevLett.120.133203

    View details for Web of Science ID 000428394800008

    View details for PubMedID 29694162

  • Characterizing isolated attosecond pulses with angular streaking OPTICS EXPRESS Li, S., Guo, Z., Coffee, R. N., Hegazy, K., Huang, Z., Natan, A., Osipov, T., Ray, D., Marinelli, A., Cryan, J. P. 2018; 26 (4): 4531–47


    We present a reconstruction algorithm for isolated attosecond pulses, which exploits the phase dependent energy modulation of a photoelectron ionized in the presence of a strong laser field. The energy modulation due to a circularly polarized laser field is manifest strongly in the angle-resolved photoelectron momentum distribution, allowing for complete reconstruction of the temporal and spectral profile of an attosecond burst. We show that this type of reconstruction algorithm is robust against counting noise and suitable for single-shot experiments. This algorithm holds potential for a variety of applications for attosecond pulse sources.

    View details for DOI 10.1364/OE.26.004531

    View details for Web of Science ID 000426268500073

    View details for PubMedID 29475303

  • Fresh-slice multicolour X-ray free-electron lasers NATURE PHOTONICS Lutman, A. A., Maxwell, T. J., MacArthur, J. P., Guetg, M. W., Berrah, N., Coffee, R. N., Ding, Y., Huang, Z., Marinelli, A., Moeller, S., Zemella, J. C. 2016; 10 (11): 745-750
  • Polarization control in an X-ray free-electron laser NATURE PHOTONICS Lutman, A. A., MacArthur, J. P., Ilchen, M., Lindahl, A. O., Buck, J., Coffee, R. N., Dakovski, G. L., Dammann, L., Ding, Y., Durr, H. A., Glaser, L., Grunert, J., Hartmann, G., Hartmann, N., Higley, D., Hirsch, K., Levashov, Y. I., Marinelli, A., Maxwell, T., Mitra, A., Moeller, S., Osipov, T., Peters, F., Planas, M., Shevchuk, I., Schlotter, W. F., Scholz, F., Seltmann, J., Viefhaus, J., Walter, P., Wolf, Z. R., Huang, Z., Nuhn, H. 2016; 10 (7): 468-472
  • Transient lattice contraction in the solid-to-plasma transition. Science advances Ferguson, K. R., Bucher, M., Gorkhover, T., Boutet, S., Fukuzawa, H., Koglin, J. E., Kumagai, Y., Lutman, A., Marinelli, A., Messerschmidt, M., Nagaya, K., Turner, J., Ueda, K., Williams, G. J., Bucksbaum, P. H., Bostedt, C. 2016; 2 (1)


    In condensed matter systems, strong optical excitations can induce phonon-driven processes that alter their mechanical properties. We report on a new phenomenon where a massive electronic excitation induces a collective change in the bond character that leads to transient lattice contraction. Single large van der Waals clusters were isochorically heated to a nanoplasma state with an intense 10-fs x-ray (pump) pulse. The structural evolution of the nanoplasma was probed with a second intense x-ray (probe) pulse, showing systematic contraction stemming from electron delocalization during the solid-to-plasma transition. These findings are relevant for any material in extreme conditions ranging from the time evolution of warm or hot dense matter to ultrafast imaging with intense x-ray pulses or, more generally, any situation that involves a condensed matter-to-plasma transition.

    View details for DOI 10.1126/sciadv.1500837

    View details for PubMedID 27152323

    View details for PubMedCentralID PMC4846449