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Brooks NJ, Dorney KM, Ellis J, Denton AE, Gentry C, Ryan SA, Nguyen QLD, Morrill DW, Kapteyn HC, Murnane MM. High-harmonic spin-shearing interferometry for spatially resolved EUV magneto-optical spectroscopy. OPTICS EXPRESS 2024; 32:19076-19087. [PMID: 38859051 DOI: 10.1364/oe.521669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/30/2024] [Indexed: 06/12/2024]
Abstract
We present a method for achieving hyperspectral magnetic imaging in the extreme ultraviolet (EUV) region based on high-harmonic generation (HHG). By interfering two mutually coherent orthogonally-polarized and laterally-sheared HHG sources, we create an EUV illumination beam with spatially-dependent ellipticity. By placing a magnetic sample in the beamline and sweeping the relative time delay between the two sources, we record a spatially resolved interferogram that is sensitive to the EUV magnetic circular dichroism of the sample. This image contains the spatially-resolved magneto-optical response of the sample at each harmonic order, and can be used to measure the magnetic properties of spatially inhomogeneous magnetic samples.
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2
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Ryan SA, Johnsen PC, Elhanoty MF, Grafov A, Li N, Delin A, Markou A, Lesne E, Felser C, Eriksson O, Kapteyn HC, Grånäs O, Murnane MM. Optically controlling the competition between spin flips and intersite spin transfer in a Heusler half-metal on sub-100-fs time scales. SCIENCE ADVANCES 2023; 9:eadi1428. [PMID: 37948525 PMCID: PMC10637748 DOI: 10.1126/sciadv.adi1428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
The direct manipulation of spins via light may provide a path toward ultrafast energy-efficient devices. However, distinguishing the microscopic processes that can occur during ultrafast laser excitation in magnetic alloys is challenging. Here, we study the Heusler compound Co2MnGa, a material that exhibits very strong light-induced spin transfers across the entire M-edge. By combining the element specificity of extreme ultraviolet high-harmonic probes with time-dependent density functional theory, we disentangle the competition between three ultrafast light-induced processes that occur in Co2MnGa: same-site Co-Co spin transfer, intersite Co-Mn spin transfer, and ultrafast spin flips mediated by spin-orbit coupling. By measuring the dynamic magnetic asymmetry across the entire M-edges of the two magnetic sublattices involved, we uncover the relative dominance of these processes at different probe energy regions and times during the laser pulse. Our combined approach enables a comprehensive microscopic interpretation of laser-induced magnetization dynamics on time scales shorter than 100 femtoseconds.
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Affiliation(s)
- Sinéad A. Ryan
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Peter C. Johnsen
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Mohamed F. Elhanoty
- Division of Materials Theory, Department of Physics and Astronomy, Uppsala University, Box-516, SE 75120, Sweden
| | - Anya Grafov
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Na Li
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Anna Delin
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, SE-10691 Stockholm, Sweden
- Swedish e-Science Research Center (SeRC), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden
| | - Anastasios Markou
- Physics Department, University of Ioannina, 45110 Ioannina, Greece
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Edouard Lesne
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - Olle Eriksson
- Division of Materials Theory, Department of Physics and Astronomy, Uppsala University, Box-516, SE 75120, Sweden
- Wallenberg Initiative Materials Science for Sustainability, Uppsala University, 75121 Uppsala, Sweden
| | - Henry C. Kapteyn
- JILA, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
- KMLabs Inc., Boulder, CO 80301, USA
| | - Oscar Grånäs
- Division of Materials Theory, Department of Physics and Astronomy, Uppsala University, Box-516, SE 75120, Sweden
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3
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Johnsen PC, Ryan SA, Gentry C, Grafov A, Kapteyn H, Murnane M. A beamline for ultrafast extreme ultraviolet magneto-optical spectroscopy in reflection near the shot noise limit. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:033001. [PMID: 37012828 DOI: 10.1063/5.0127119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/30/2023] [Indexed: 06/19/2023]
Abstract
High harmonic generation (HHG) makes it possible to measure spin and charge dynamics in materials on femtosecond to attosecond timescales. However, the extreme nonlinear nature of the high harmonic process means that intensity fluctuations can limit measurement sensitivity. Here we present a noise-canceled, tabletop high harmonic beamline for time-resolved reflection mode spectroscopy of magnetic materials. We use a reference spectrometer to independently normalize the intensity fluctuations of each harmonic order and eliminate long term drift, allowing us to make spectroscopic measurements near the shot noise limit. These improvements allow us to significantly reduce the integration time required for high signal-to-noise (SNR) measurements of element-specific spin dynamics. Looking forward, improvements in the HHG flux, optical coatings, and grating design can further reduce the acquisition time for high SNR measurements by 1-2 orders of magnitude, enabling dramatically improved sensitivity to spin, charge, and phonon dynamics in magnetic materials.
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Affiliation(s)
- Peter C Johnsen
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Sinéad A Ryan
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Christian Gentry
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Anya Grafov
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Henry Kapteyn
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
| | - Margaret Murnane
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309-0440, USA
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4
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Li Q, Xu X, Wu Y, Zou D, Yin Y, Yu T. Generation of single circularly polarized attosecond pulses from near-critical density plasma irradiated by a two-color co-rotating circularly polarized laser. OPTICS EXPRESS 2022; 30:40063-40074. [PMID: 36298945 DOI: 10.1364/oe.472982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
In this paper, a new method is proposed to efficiently generate a single intense attosecond pulse with circular polarization (CP) through the interaction of an intense driving laser with a near-critical density plasma target. The driving laser is composed of two co-rotating CP lasers with similar frequencies but different pulse widths. When the matching condition is satisfied, the combined field is modulated to a short intense pulse followed by a weak tail. The resulting laser falling edge becomes steeper than the initial sub-pulses, which induces a quick one-time oscillation of the target surface. Meanwhile, the tail guarantees the energy to be compressed simultaneously in both polarization directions to the same extent, so that a single CP attosecond pulse can be produced efficiently and robustly via our method, which has been confirmed through extensive numerical simulations. In addition, our method makes it possible to generate a single CP attosecond pulse even for multi-cycle pulses that are already available for existing laser systems. This provides a novel way to advance the investigation of chiral-sensitive light-matter interactions in attosecond scales.
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5
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Li Q, Xu X, Wu Y, Yin Y, Zou D, Yu T. Efficient high-order harmonics generation from overdense plasma irradiated by a two-color co-rotating circularly polarized laser pulse. OPTICS EXPRESS 2022; 30:15470-15481. [PMID: 35473266 DOI: 10.1364/oe.459866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/13/2022] [Indexed: 06/14/2023]
Abstract
High-order harmonics generated from the interaction between a two-color circularly polarized laser and overdense plasma is proposed analytically and investigated numerically. By mixing two circularly polarized lasers rotating in the same direction with different frequencies (ω0, 2ω0), the laser envelope is modulated to oscillate at the laser fundamental frequency while the peak intensity of each cycle becomes greater than that of the monochromatic light. This feature makes the plasma oscillate more violently and frequently under the striking of the two-color laser than the monochromatic one, thereby generating stronger harmonics and attosecond pulses. In addition, the incorporation of the 2ω0 light greatly expands the spectral width of harmonics, which facilitates the production of shorter attosecond pulses. Particle-in-cell simulations prove that under the same condition, the harmonic radiation efficiency in the two-color laser case can be improved by orders of magnitude, and isolated attosecond pulses can be even generated as a bonus in some cases.
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6
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Ayuso D, Ordonez AF, Decleva P, Ivanov M, Smirnova O. Strong chiral response in non-collinear high harmonic generation driven by purely electric-dipole interactions. OPTICS EXPRESS 2022; 30:4659-4667. [PMID: 35209442 DOI: 10.1364/oe.444210] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
High harmonic generation (HHG) records the ultrafast electronic response of matter to light, encoding key properties of the interrogated quantum system, such as chirality. The first implementation of chiral HHG [Cireasa et al, Nat. Phys.11, 654 (2015)10.1038/nphys3369] relied on the weak electronic response of a medium of randomly oriented chiral molecules to the magnetic component of an elliptically polarized wave, yielding relatively weak chiro-optical signals. Here we apply state-of-the-art semi-analytical modelling to show that elliptically polarized light can drive a strong chiral response in chiral molecules via purely electric-dipole interactions - the magnetic component of the wave does not participate at all. This strong chiro-optical response, which remains hidden in standard HHG experiments, can be mapped into the macroscopic far-field signal using a non-collinear configuration, creating new opportunities for imaging chiral matter and chiral dynamics on ultrafast time scales.
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7
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Investigating Coherent Magnetization Control with Ultrashort THz Pulses. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031323] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Coherent terahertz control of magnetization dynamics is an area of current interest due to its great potential for the realization of magnetization control on ultrafast timescales in commercial devices. Here we report on an experiment realized at the THz beamline of the free electron laser FLASH at DESY which offers a tunable terahertz radiation source and spontaneously synchronized free-electron laser X-ray pulses to resonantly probe the magnetization state of a ferromagnetic film. In this proof-of-principle experiment, we have excited a thin Permalloy film at different THz wavelengths and recorded the induced magnetization dynamics with photons resonantly tuned to the Ni M2,3 absorption edge. For THz pump pulses including higher orders of the undulator source we observed demagnetization dynamics, which precise shape depended on the employed fundamental wavelength of the undulator source. Analyzing the shape in detail, we can reconstruct the temporal profile of the electric field of the THz pump pulse. This offers a new method for the realization of an in-situ terahertz beamline diagnostic which will help researchers to adjust the pulse characteristics as needed, for example, for future studies of THz induced coherent control of magnetization dynamics.
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Lloyd-Hughes J, Oppeneer PM, Pereira Dos Santos T, Schleife A, Meng S, Sentef MA, Ruggenthaler M, Rubio A, Radu I, Murnane M, Shi X, Kapteyn H, Stadtmüller B, Dani KM, da Jornada FH, Prinz E, Aeschlimann M, Milot RL, Burdanova M, Boland J, Cocker T, Hegmann F. The 2021 ultrafast spectroscopic probes of condensed matter roadmap. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:353001. [PMID: 33951618 DOI: 10.1088/1361-648x/abfe21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
In the 60 years since the invention of the laser, the scientific community has developed numerous fields of research based on these bright, coherent light sources, including the areas of imaging, spectroscopy, materials processing and communications. Ultrafast spectroscopy and imaging techniques are at the forefront of research into the light-matter interaction at the shortest times accessible to experiments, ranging from a few attoseconds to nanoseconds. Light pulses provide a crucial probe of the dynamical motion of charges, spins, and atoms on picosecond, femtosecond, and down to attosecond timescales, none of which are accessible even with the fastest electronic devices. Furthermore, strong light pulses can drive materials into unusual phases, with exotic properties. In this roadmap we describe the current state-of-the-art in experimental and theoretical studies of condensed matter using ultrafast probes. In each contribution, the authors also use their extensive knowledge to highlight challenges and predict future trends.
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Affiliation(s)
- J Lloyd-Hughes
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, PO Box 516, S-75120 Uppsala, Sweden
| | - T Pereira Dos Santos
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - A Schleife
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - S Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - M Ruggenthaler
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
| | - A Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science (CFEL), 22761 Hamburg, Germany
- Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco UPV/EHU 20018 San Sebastián, Spain
- Center for Computational Quantum Physics (CCQ), The Flatiron Institute, 162 Fifth Avenue, New York, NY, 10010, United States of America
| | - I Radu
- Department of Physics, Freie Universität Berlin, Germany
- Max Born Institute, Berlin, Germany
| | - M Murnane
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - X Shi
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - H Kapteyn
- JILA, University of Colorado and NIST, Boulder, CO, United States of America
| | - B Stadtmüller
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - K M Dani
- Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Japan
| | - F H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, 94305, CA, United States of America
| | - E Prinz
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - M Aeschlimann
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - R L Milot
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - M Burdanova
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom
| | - J Boland
- Photon Science Institute, Department of Electrical and Electronic Engineering, University of Manchester, United Kingdom
| | - T Cocker
- Michigan State University, United States of America
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9
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Möller C, Probst H, Otto J, Stroh K, Mahn C, Steil S, Moshnyaga V, Jansen GSM, Steil D, Mathias S. Ultrafast element-resolved magneto-optics using a fiber-laser-driven extreme ultraviolet light source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:065107. [PMID: 34243510 DOI: 10.1063/5.0050883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/16/2021] [Indexed: 06/13/2023]
Abstract
We present a novel setup to measure the transverse magneto-optical Kerr effect in the extreme ultraviolet spectral range based on a fiber laser amplifier system with a repetition rate between 100 and 300 kHz, which we use to measure element-resolved demagnetization dynamics. The setup is equipped with a strong electromagnet and a cryostat, allowing measurements between 10 and 420 K using magnetic fields up to 0.86 T. The performance of our setup is demonstrated by a set of temperature- and time-dependent magnetization measurements with elemental resolution.
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Affiliation(s)
- Christina Möller
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Henrike Probst
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Johannes Otto
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Karen Stroh
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Carsten Mahn
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Sabine Steil
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Vasily Moshnyaga
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - G S Matthijs Jansen
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Daniel Steil
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Stefan Mathias
- I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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10
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Eschenlohr A. Spin dynamics at interfaces on femtosecond timescales. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:013001. [PMID: 33034305 DOI: 10.1088/1361-648x/abb519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The excitation of magnetically ordered materials with ultrashort laser pulses results in magnetization dynamics on femto- to picosecond timescales. These non-equilibrium spin dynamics have emerged as a rapidly developing research field in recent years. Unraveling the fundamental microscopic processes in the interaction of ultrashort optical pulses with the charge, spin, orbital, and lattice degrees of freedom in magnetic materials shows the potential for controlling spin dynamics on their intrinsic timescales and thereby bring spintronics applications into the femtosecond range. In particular, femtosecond spin currents offer fascinating new possibilities to manipulate magnetization in an ultrafast and non-local manner, via spin injection and spin transfer torque at the interfaces of ferromagnetic layered structures. This topical review covers recent progress on spin dynamics at interfaces on femtosecond time scales. The development of the field of ultrafast spin dynamics in ferromagnetic heterostructures will be reviewed, starting from spin currents propagating on nanometer length scales through layered structures before focusing on femtosecond spin transfer at interfaces. The properties of these ultrafast spin-dependent charge currents will be discussed, as well as the materials dependence of femtosecond spin injection, the role of the interface properties, and competing microscopic processes leading to a loss of spin polarization on sub-picosecond timescales.
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Affiliation(s)
- A Eschenlohr
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany
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11
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Wang C, Liu Y. Ultrafast optical manipulation of magnetic order in ferromagnetic materials. NANO CONVERGENCE 2020; 7:35. [PMID: 33170368 PMCID: PMC7655883 DOI: 10.1186/s40580-020-00246-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/28/2020] [Indexed: 05/08/2023]
Abstract
The interaction between ultrafast lasers and magnetic materials is an appealing topic. It not only involves interesting fundamental questions that remain inconclusive and hence need further investigation, but also has the potential to revolutionize data storage technologies because such an opto-magnetic interaction provides an ultrafast and energy-efficient means to control magnetization. Fruitful progress has been made in this area over the past quarter century. In this paper, we review the state-of-the-art experimental and theoretical studies on magnetization dynamics and switching in ferromagnetic materials that are induced by ultrafast lasers. We start by describing the physical mechanisms of ultrafast demagnetization based on different experimental observations and theoretical methods. Both the spin-flip scattering theory and the superdiffusive spin transport model will be discussed in detail. Then, we will discuss laser-induced torques and resultant magnetization dynamics in ferromagnetic materials. Recent developments of all-optical switching (AOS) of ferromagnetic materials towards ultrafast magnetic storage and memory will also be reviewed, followed by the perspectives on the challenges and future directions in this emerging area.
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Affiliation(s)
- Chuangtang Wang
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Yongmin Liu
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA.
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA.
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12
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Element-Specific Magnetization Dynamics of Complex Magnetic Systems Probed by Ultrafast Magneto-Optical Spectroscopy. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10217580] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The vision to manipulate and control magnetism with light is driven on the one hand by fundamental questions of direct and indirect photon-spin interactions, and on the other hand by the necessity to cope with ever growing data volumes, requiring radically new approaches on how to write, read and process information. Here, we present two complementary experimental geometries to access the element-specific magnetization dynamics of complex magnetic systems via ultrafast magneto-optical spectroscopy in the extreme ultraviolet spectral range. First, we employ linearly polarized radiation of a free electron laser facility to demonstrate decoupled dynamics of the two sublattices of an FeGd alloy, a prerequisite for all-optical magnetization switching. Second, we use circularly polarized radiation generated in a laboratory-based high harmonic generation setup to show optical inter-site spin transfer in a CoPt alloy, a mechanism which only very recently has been predicted to mediate ultrafast metamagnetic phase transitions.
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13
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Huang L, Lee SH, Kim SD, Shim JH, Shin HJ, Kim S, Park J, Park SY, Choi YS, Kim HJ, Hong JI, Kim DE, Kim DH. Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films. Sci Rep 2020; 10:15843. [PMID: 32985564 PMCID: PMC7522994 DOI: 10.1038/s41598-020-72855-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
We report a universal terahertz (THz) emission behavior from simple Ni, Fe, and Co metallic ferromagnetic films, triggered by the femtosecond laser pulse and subsequent photoinduced demagnetization on an ultrafast time scale. THz emission behavior in ferromagnetic films is found to be consistent with initial magnetization states controlled by external fields, where the hysteresis of the maximal THz emission signal is observed to be well-matched with the magnetic hysteresis curve. It is experimentally demonstrated that the ultrafast THz emission by the photoinduced demagnetization is controllable in a simple way by external fields as well as pump fluences.
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Affiliation(s)
- Lin Huang
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea
| | - Sang-Hyuk Lee
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea
| | - Seon-Dae Kim
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea
| | - Je-Ho Shim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Hee Jun Shin
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, South Korea
| | - Seongheun Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, South Korea
| | - Jaehun Park
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, South Korea
| | - Seung-Young Park
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Yeon Suk Choi
- Center for Scientific Instrumentation, Korea Basic Science Institute, Daejeon, 34133, South Korea
| | - Hyun-Joong Kim
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Jung-Il Hong
- Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, 42988, South Korea
| | - Dong Eon Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, Pohang, 37673, South Korea.,Max Planck POSTECH/KOREA Research Initiative, Pohang, 37673, South Korea
| | - Dong-Hyun Kim
- Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea.
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14
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Yao K, Willems F, von Korff Schmising C, Strüber C, Hessing P, Pfau B, Schick D, Engel D, Gerlinger K, Schneider M, Eisebitt S. A tabletop setup for ultrafast helicity-dependent and element-specific absorption spectroscopy and scattering in the extreme ultraviolet spectral range. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:093001. [PMID: 33003828 DOI: 10.1063/5.0013928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
Further advances in the field of ultrafast magnetization dynamics require experimental tools to measure the spin and electron dynamics with element-specificity and femtosecond temporal resolution. We present a new laboratory setup for two complementary experiments with light in the extreme ultraviolet (XUV) spectral range. One experiment is designed for polarization-dependent transient spectroscopy, particularly for simultaneous measurements of magnetic circular dichroism (MCD) at the 3p resonances of the 3d transition metals Fe, Co, and Ni. The second instrument is designed for resonant small-angle scattering experiments with monochromatic light allowing us to monitor spin dynamics with spatial information on the nanometer scale. We combine a high harmonic generation (HHG) source with a phase shifter to obtain XUV pulses with variable polarization and a flux of about (3 ± 1) × 1010 photons/s/harmonic at 60 eV at the source. A dedicated reference spectrometer effectively reduces the intensity fluctuations of the HHG spectrum to below 0.12% rms. We demonstrate the capabilities of the setup by capturing the energy- and polarization-dependent absorption of a thin Co film as well as the time-resolved small-angle scattering in a magnetic-domain network of a Co/Pt multilayer. The new laboratory setup allows systematic studies of optically induced spin and electron dynamics with element-specificity, particularly with MCD as the contrast mechanism with femtosecond temporal resolution and an unprecedented signal-to-noise ratio.
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Affiliation(s)
- Kelvin Yao
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Felix Willems
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Clemens von Korff Schmising
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Christian Strüber
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Piet Hessing
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Bastian Pfau
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Daniel Schick
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Dieter Engel
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Kathinka Gerlinger
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Michael Schneider
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Stefan Eisebitt
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
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15
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Dewhurst JK, Willems F, Elliott P, Li QZ, Schmising CVK, Strüber C, Engel DW, Eisebitt S, Sharma S. Element Specificity of Transient Extreme Ultraviolet Magnetic Dichroism. PHYSICAL REVIEW LETTERS 2020; 124:077203. [PMID: 32142343 DOI: 10.1103/physrevlett.124.077203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
In this work we combine theory and experiment to study transient magnetic circular dichroism (TRMCD) in the extreme ultraviolet spectral range in bulk Co and CoPt. We use the ab initio method of real-time time-dependent density functional theory to simulate the magnetization dynamics in the presence of short laser pulses. From this we demonstrate how TRMCD may be calculated using an approximation to the excited-state linear response. We apply this approximation to Co and CoPt and show computationally that element-specific dynamics of the local spin moments can be extracted from the TRMCD in the extreme ultraviolet energy range, as is commonly assumed. We then compare our theoretical prediction for the TRMCD for CoPt with experimental measurement and find excellent agreement at many different frequencies including the M_{23} edge of Co and N_{67} and O_{23} edges of Pt.
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Affiliation(s)
- J K Dewhurst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - F Willems
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - P Elliott
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - Q Z Li
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - C von Korff Schmising
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - C Strüber
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - D W Engel
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - S Eisebitt
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - S Sharma
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
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16
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Willems F, von Korff Schmising C, Strüber C, Schick D, Engel DW, Dewhurst JK, Elliott P, Sharma S, Eisebitt S. Optical inter-site spin transfer probed by energy and spin-resolved transient absorption spectroscopy. Nat Commun 2020; 11:871. [PMID: 32054855 PMCID: PMC7018696 DOI: 10.1038/s41467-020-14691-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 01/27/2020] [Indexed: 11/09/2022] Open
Abstract
Optically driven spin transport is the fastest and most efficient process to manipulate macroscopic magnetization as it does not rely on secondary mechanisms to dissipate angular momentum. In the present work, we show that such an optical inter-site spin transfer (OISTR) from Pt to Co emerges as a dominant mechanism governing the ultrafast magnetization dynamics of a CoPt alloy. To demonstrate this, we perform a joint theoretical and experimental investigation to determine the transient changes of the helicity dependent absorption in the extreme ultraviolet spectral range. We show that the helicity dependent absorption is directly related to changes of the transient spin-split density of states, allowing us to link the origin of OISTR to the available minority states above the Fermi level. This makes OISTR a general phenomenon in optical manipulation of multi-component magnetic systems.
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Affiliation(s)
- Felix Willems
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
| | - Clemens von Korff Schmising
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany.
| | - Christian Strüber
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
| | - Daniel Schick
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
| | - Dieter W Engel
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
| | - J K Dewhurst
- Max-Planck-Institute for Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Peter Elliott
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
| | - Sangeeta Sharma
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
| | - Stefan Eisebitt
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489, Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623, Berlin, Germany
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17
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Hofherr M, Häuser S, Dewhurst JK, Tengdin P, Sakshath S, Nembach HT, Weber ST, Shaw JM, Silva TJ, Kapteyn HC, Cinchetti M, Rethfeld B, Murnane MM, Steil D, Stadtmüller B, Sharma S, Aeschlimann M, Mathias S. Ultrafast optically induced spin transfer in ferromagnetic alloys. SCIENCE ADVANCES 2020; 6:eaay8717. [PMID: 32010774 PMCID: PMC6968944 DOI: 10.1126/sciadv.aay8717] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 10/09/2019] [Indexed: 05/23/2023]
Abstract
The vision of using light to manipulate electronic and spin excitations in materials on their fundamental time and length scales requires new approaches in experiment and theory to observe and understand these excitations. The ultimate speed limit for all-optical manipulation requires control schemes for which the electronic or magnetic subsystems of the materials are coherently manipulated on the time scale of the laser excitation pulse. In our work, we provide experimental evidence of such a direct, ultrafast, and coherent spin transfer between two magnetic subsystems of an alloy of Fe and Ni. Our experimental findings are fully supported by time-dependent density functional theory simulations and, hence, suggest the possibility of coherently controlling spin dynamics on subfemtosecond time scales, i.e., the birth of the research area of attomagnetism.
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Affiliation(s)
- M. Hofherr
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
- Graduate School of Excellence Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - S. Häuser
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - J. K. Dewhurst
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - P. Tengdin
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - S. Sakshath
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - H. T. Nembach
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - S. T. Weber
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - J. M. Shaw
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - T. J. Silva
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - H. C. Kapteyn
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - M. Cinchetti
- Experimentelle Physik VI, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - B. Rethfeld
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - M. M. Murnane
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - D. Steil
- Georg-August-Universität Göttingen, I. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - B. Stadtmüller
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
- Graduate School of Excellence Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - S. Sharma
- Max Born Institute for Nonlinear Optics, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - M. Aeschlimann
- Technische Universität Kaiserslautern und Landesforschungszentrum OPTIMAS, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - S. Mathias
- Georg-August-Universität Göttingen, I. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- Corresponding author.
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18
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Tengdin P, Gentry C, Blonsky A, Zusin D, Gerrity M, Hellbrück L, Hofherr M, Shaw J, Kvashnin Y, Delczeg-Czirjak EK, Arora M, Nembach H, Silva TJ, Mathias S, Aeschlimann M, Kapteyn HC, Thonig D, Koumpouras K, Eriksson O, Murnane MM. Direct light-induced spin transfer between different elements in a spintronic Heusler material via femtosecond laser excitation. SCIENCE ADVANCES 2020; 6:eaaz1100. [PMID: 32010777 PMCID: PMC6968936 DOI: 10.1126/sciadv.aaz1100] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 11/26/2019] [Indexed: 05/23/2023]
Abstract
Heusler compounds are exciting materials for future spintronics applications because they display a wide range of tunable electronic and magnetic interactions. Here, we use a femtosecond laser to directly transfer spin polarization from one element to another in a half-metallic Heusler material, Co2MnGe. This spin transfer initiates as soon as light is incident on the material, demonstrating spatial transfer of angular momentum between neighboring atomic sites on time scales < 10 fs. Using ultrafast high harmonic pulses to simultaneously and independently probe the magnetic state of two elements during laser excitation, we find that the magnetization of Co is enhanced, while that of Mn rapidly quenches. Density functional theory calculations show that the optical excitation directly transfers spin from one magnetic sublattice to another through preferred spin-polarized excitation pathways. This direct manipulation of spins via light provides a path toward spintronic devices that can operate on few-femtosecond or faster time scales.
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Affiliation(s)
- Phoebe Tengdin
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Christian Gentry
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Adam Blonsky
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Dmitriy Zusin
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Michael Gerrity
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Lukas Hellbrück
- Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - Moritz Hofherr
- Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - Justin Shaw
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Yaroslav Kvashnin
- Department of Physics and Astronomy, University Uppsala, S-75120 Uppsala, Sweden
| | | | - Monika Arora
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Hans Nembach
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Tom J. Silva
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, CO 80305, USA
| | - Stefan Mathias
- Georg-August-Universität Göttingen, I. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Martin Aeschlimann
- Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany
| | - Henry C. Kapteyn
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
| | - Danny Thonig
- Department of Physics and Astronomy, University Uppsala, S-75120 Uppsala, Sweden
- School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden
| | | | - Olle Eriksson
- Department of Physics and Astronomy, University Uppsala, S-75120 Uppsala, Sweden
- School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden
| | - Margaret M. Murnane
- Department of Physics and JILA, University of Colorado and NIST, Boulder, CO 80309, USA
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19
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Willems F, Sharma S, V Korff Schmising C, Dewhurst JK, Salemi L, Schick D, Hessing P, Strüber C, Engel WD, Eisebitt S. Magneto-Optical Functions at the 3p Resonances of Fe, Co, and Ni: Ab initio Description and Experiment. PHYSICAL REVIEW LETTERS 2019; 122:217202. [PMID: 31283338 DOI: 10.1103/physrevlett.122.217202] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 06/09/2023]
Abstract
We present experimental data and a complete theoretical description of the magneto-optical contributions to the complex refractive index in the extreme ultraviolet (XUV) range covering the 3p resonances of Fe, Co, and Ni. The direct comparison of the two allows us to conclude that many-body corrections to the ground state and local field effects are crucial for an accurate description of M-edge spectra. Our results are relevant for investigation of static magnetization, via XUV spectroscopy of multielement systems, as well as the dynamics of magnetization, as needed in the study of femtomagnetism and spintronics.
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Affiliation(s)
- F Willems
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - S Sharma
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - C V Korff Schmising
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - J K Dewhurst
- Max-Planck-Institute for Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - L Salemi
- Department of Physics and Astronomy, Materials Theory, Uppsala University, 75120 Uppsala, Sweden
| | - D Schick
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - P Hessing
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - C Strüber
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - W D Engel
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - S Eisebitt
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
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20
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M. B, A. M, G. V, M. V, J.-Y. B. Multiscale temporal probing of elemental ultrafast magnetization dynamics in permalloy using High order Harmonics. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201920502013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Chemically selective magnetization dynamics is probed in Ni8()Fe20 with High order Harmonics over a large temporal scale. It is shown that the ratio between effective exchange interaction constants of each element can be retrieved experimentally.
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21
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Impulsive UV-pump/X-ray probe study of vibrational dynamics in glycine. Sci Rep 2018; 8:15466. [PMID: 30337694 PMCID: PMC6193943 DOI: 10.1038/s41598-018-33607-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/27/2018] [Indexed: 11/24/2022] Open
Abstract
We report an ab-initio study of a pump-probe experiment on the amino-acid glycine. We consider an UV pump followed by an X-ray probe tuned to carbon K-edge and study the vibronic structure of the core transition. The simulated experiment is feasible using existing free electron laser or high harmonic generation sources and thanks to the localization of the core orbitals posseses chemical selectivity. The present theory applies to other experimental schemes, including the use of a THz probe, available with present soft X-ray free electron lasers and/or high harmonic generation sources.
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22
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Gort R, Bühlmann K, Däster S, Salvatella G, Hartmann N, Zemp Y, Holenstein S, Stieger C, Fognini A, Michlmayr TU, Bähler T, Vaterlaus A, Acremann Y. Early Stages of Ultrafast Spin Dynamics in a 3d Ferromagnet. PHYSICAL REVIEW LETTERS 2018; 121:087206. [PMID: 30192573 DOI: 10.1103/physrevlett.121.087206] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Prior to the development of pulsed lasers, one assigned a single local temperature to the lattice, the electron gas, and the spins. With the availability of ultrafast laser sources, one can now drive the temperature of these reservoirs out of equilibrium. Thus, the solid shows new internal degrees of freedom characterized by individual temperatures of the electron gas T_{e}, the lattice T_{l} and the spins T_{s}. We demonstrate an analogous behavior in the spin polarization of a ferromagnet in an ultrafast demagnetization experiment: At the Fermi energy, the polarization is reduced faster than at deeper in the valence band. Therefore, on the femtosecond time scale, the magnetization as a macroscopic quantity does not provide the full picture of the spin dynamics: The spin polarization separates into different parts similar to how the single temperature paradigm changed with the development of ultrafast lasers.
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Affiliation(s)
- R Gort
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - K Bühlmann
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - S Däster
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - G Salvatella
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - N Hartmann
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Y Zemp
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - S Holenstein
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Department of Physics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - C Stieger
- Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - A Fognini
- Department of Quantum Nanoscience, TU Delft, 2628 CD Delft, Netherlands
| | - T U Michlmayr
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - T Bähler
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - A Vaterlaus
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Y Acremann
- Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland
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23
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You W, Tengdin P, Chen C, Shi X, Zusin D, Zhang Y, Gentry C, Blonsky A, Keller M, Oppeneer PM, Kapteyn H, Tao Z, Murnane M. Revealing the Nature of the Ultrafast Magnetic Phase Transition in Ni by Correlating Extreme Ultraviolet Magneto-Optic and Photoemission Spectroscopies. PHYSICAL REVIEW LETTERS 2018; 121:077204. [PMID: 30169091 DOI: 10.1103/physrevlett.121.077204] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Indexed: 06/08/2023]
Abstract
By correlating time- and angle-resolved photoemission and time-resolved transverse magneto-optical Kerr effect measurements, both at extreme ultraviolet wavelengths, we uncover the universal nature of the ultrafast photoinduced magnetic phase transition in Ni. This allows us to explain the ultrafast magnetic response of Ni at all laser fluences-from a small reduction of the magnetization at low laser fluences, to complete quenching at high laser fluences. Both probe methods exhibit the same demagnetization and recovery timescales. The spin system absorbs the energy required to proceed through a magnetic phase transition within 20 fs after the peak of the pump pulse. However, the spectroscopic signatures of demagnetization of the material appear only after ≈200 fs and the subsequent recovery of magnetization on timescales ranging from 500 fs to >70 ps. We also provide evidence of two competing channels with two distinct timescales in the recovery process that suggest the presence of coexisting phases in the material.
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Affiliation(s)
- Wenjing You
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Phoebe Tengdin
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Cong Chen
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Xun Shi
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Dmitriy Zusin
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Yingchao Zhang
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Christian Gentry
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Adam Blonsky
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Mark Keller
- National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, Colorado 80305, USA
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Henry Kapteyn
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Zhensheng Tao
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
| | - Margaret Murnane
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
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24
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Zhang GP, Si MS, Murakami M, Bai YH, George TF. Generating high-order optical and spin harmonics from ferromagnetic monolayers. Nat Commun 2018; 9:3031. [PMID: 30072711 PMCID: PMC6072758 DOI: 10.1038/s41467-018-05535-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 07/05/2018] [Indexed: 11/08/2022] Open
Abstract
High-order harmonic generation (HHG) in solids has entered a new phase of intensive research, with envisioned band-structure mapping on an ultrashort time scale. This partly benefits from a flurry of new HHG materials discovered, but so far has missed an important group. HHG in magnetic materials should have profound impact on future magnetic storage technology advances. Here we introduce and demonstrate HHG in ferromagnetic monolayers. We find that HHG carries spin information and sensitively depends on the relativistic spin-orbit coupling; and if they are dispersed into the crystal momentum k space, harmonics originating from real transitions can be k-resolved and carry the band structure information. Geometrically, the HHG signal is sensitive to spatial orientations of monolayers. Different from the optical counterpart, the spin HHG, though probably weak, only appears at even orders, a consequence of SU(2) symmetry. Our findings open an unexplored frontier-magneto-high-order harmonic generation.
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Affiliation(s)
- G P Zhang
- Department of Physics, Indiana State University, Terre Haute, IN, 47809, USA.
| | - M S Si
- Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - M Murakami
- Department of Physics, Indiana State University, Terre Haute, IN, 47809, USA
| | - Y H Bai
- Office of Information Technology, Indiana State University, Terre Haute, IN, 47809, USA
| | - Thomas F George
- Office of the Chancellor Departments of Chemistry & Biochemistry, Physics & Astronomy University of Missouri-St. Louis, St. Louis, MO, 63121, USA
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25
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Yue S, Fu S, Li J, Zhang X, Feng Y, Hu B, Du H. A redshift mechanism of high-order harmonics: Change of ionization energy. J Chem Phys 2018; 148:234304. [PMID: 29935501 DOI: 10.1063/1.5031210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We theoretically study the high-order harmonic generation of H2+ and its isotopes beyond the Born-Oppenheimer dynamics. It is surprising that the spectral redshift can still be observed in high harmonic spectra of H2+ driven by a sinusoidal laser pulse in which the trailing (leading) edge of the laser pulse is nonexistent. The results confirm that this spectral redshift originates from the reduction in ionization energy between recombination time and ionization time, which is obviously different from the nonadiabatic spectral redshift induced by the falling edge of the laser pulse. Additionally, the improved instantaneous frequency of harmonics by considering the changeable ionization energy can deeply verify our results. Therefore, this new mechanism must be taken into account when one uses the nonadiabatic spectral redshift to retrieve the nuclear motion.
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Affiliation(s)
- Shengjun Yue
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Silin Fu
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Jinbin Li
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Xiao Zhang
- Center for Interdisciplinary Studies and Key Laboratory for Magnetism and Magnetic Materials of the MoE, Lanzhou University, Lanzhou 730000, China
| | - Yongkang Feng
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Bitao Hu
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Hongchuan Du
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
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26
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Popmintchev D, Galloway BR, Chen MC, Dollar F, Mancuso CA, Hankla A, Miaja-Avila L, O'Neil G, Shaw JM, Fan G, Ališauskas S, Andriukaitis G, Balčiunas T, Mücke OD, Pugzlys A, Baltuška A, Kapteyn HC, Popmintchev T, Murnane MM. Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua. PHYSICAL REVIEW LETTERS 2018; 120:093002. [PMID: 29547333 DOI: 10.1103/physrevlett.120.093002] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/10/2017] [Indexed: 05/16/2023]
Abstract
Recent advances in high-order harmonic generation have made it possible to use a tabletop-scale setup to produce spatially and temporally coherent beams of light with bandwidth spanning 12 octaves, from the ultraviolet up to x-ray photon energies >1.6 keV. Here we demonstrate the use of this light for x-ray-absorption spectroscopy at the K- and L-absorption edges of solids at photon energies near 1 keV. We also report x-ray-absorption spectroscopy in the water window spectral region (284-543 eV) using a high flux high-order harmonic generation x-ray supercontinuum with 10^{9} photons/s in 1% bandwidth, 3 orders of magnitude larger than has previously been possible using tabletop sources. Since this x-ray radiation emerges as a single attosecond-to-femtosecond pulse with peak brightness exceeding 10^{26} photons/s/mrad^{2}/mm^{2}/1% bandwidth, these novel coherent x-ray sources are ideal for probing the fastest molecular and materials processes on femtosecond-to-attosecond time scales and picometer length scales.
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Affiliation(s)
| | | | - Ming-Chang Chen
- National Tsing Hua University, Institute of Photonics Technologies, Hsinchu 30013, Taiwan
| | - Franklin Dollar
- JILA, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA
| | | | - Amelia Hankla
- JILA, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA
| | - Luis Miaja-Avila
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Galen O'Neil
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Justin M Shaw
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Guangyu Fan
- Photonics Institute, TU Wien, Gusshausstrasse 27-387, A-1040 Vienna, Austria
| | - Skirmantas Ališauskas
- Photonics Institute, TU Wien, Gusshausstrasse 27-387, A-1040 Vienna, Austria
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg, Germany
| | | | - Tadas Balčiunas
- Photonics Institute, TU Wien, Gusshausstrasse 27-387, A-1040 Vienna, Austria
| | - Oliver D Mücke
- Center for Free Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Audrius Pugzlys
- Photonics Institute, TU Wien, Gusshausstrasse 27-387, A-1040 Vienna, Austria
| | - Andrius Baltuška
- Photonics Institute, TU Wien, Gusshausstrasse 27-387, A-1040 Vienna, Austria
| | - Henry C Kapteyn
- JILA, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA
| | - Tenio Popmintchev
- JILA, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA
| | - Margaret M Murnane
- JILA, University of Colorado at Boulder, Boulder, Colorado 80309-0440, USA
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27
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Tengdin P, You W, Chen C, Shi X, Zusin D, Zhang Y, Gentry C, Blonsky A, Keller M, Oppeneer PM, Kapteyn HC, Tao Z, Murnane MM. Critical behavior within 20 fs drives the out-of-equilibrium laser-induced magnetic phase transition in nickel. SCIENCE ADVANCES 2018; 4:eaap9744. [PMID: 29511738 PMCID: PMC5834307 DOI: 10.1126/sciadv.aap9744] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/31/2018] [Indexed: 05/23/2023]
Abstract
It has long been known that ferromagnets undergo a phase transition from ferromagnetic to paramagnetic at the Curie temperature, associated with critical phenomena such as a divergence in the heat capacity. A ferromagnet can also be transiently demagnetized by heating it with an ultrafast laser pulse. However, to date, the connection between out-of-equilibrium and equilibrium phase transitions, or how fast the out-of-equilibrium phase transitions can proceed, was not known. By combining time- and angle-resolved photoemission with time-resolved transverse magneto-optical Kerr spectroscopies, we show that the same critical behavior also governs the ultrafast magnetic phase transition in nickel. This is evidenced by several observations. First, we observe a divergence of the transient heat capacity of the electron spin system preceding material demagnetization. Second, when the electron temperature is transiently driven above the Curie temperature, we observe an extremely rapid change in the material response: The spin system absorbs sufficient energy within the first 20 fs to subsequently proceed through the phase transition, whereas demagnetization and the collapse of the exchange splitting occur on much longer, fluence-independent time scales of ~176 fs. Third, we find that the transient electron temperature alone dictates the magnetic response. Our results are important because they connect the out-of-equilibrium material behavior to the strongly coupled equilibrium behavior and uncover a new time scale in the process of ultrafast demagnetization.
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Affiliation(s)
- Phoebe Tengdin
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Wenjing You
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Cong Chen
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Xun Shi
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Dmitriy Zusin
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Yingchao Zhang
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Christian Gentry
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Adam Blonsky
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | | | - Peter M. Oppeneer
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - Henry C. Kapteyn
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Zhensheng Tao
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
| | - Margaret M. Murnane
- Department of Physics and JILA, University of Colorado and National Institute of Standards and Technology (NIST), Boulder, CO 80309, USA
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28
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Chen ZY, Li XY, Li BY, Chen M, Liu F. Isolated elliptically polarized attosecond soft X-ray with high-brilliance using polarization gating of harmonics from relativistic plasmas at oblique incidence. OPTICS EXPRESS 2018; 26:4572-4580. [PMID: 29475306 DOI: 10.1364/oe.26.004572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
The production of intense isolated attosecond pulse is a major goal in ultrafast research. Recent advances in high harmonic generation from relativistic plasma mirrors under oblique incidence interactions gave rise to photon-rich attosecond pulses with circular or elliptical polarization. However, to achieve an isolated elliptical attosecond pulse via polarization gating using currently available long driving pulses remains a challenge, because polarization gating of high harmonics from relativistic plasmas is assumed only possible at normal or near-normal incidence. Here we numerically demonstrate a scheme around this problem. We show that via control of plasma dynamics by managing laser polarization, it is possible to gate an intense single attosecond pulse with high ellipticity extending to the soft X-ray regime at oblique incidence. This approach thus paves the way towards a powerful tool enabling high-time-resolution probe of dynamics of chiral systems and magnetic materials with current laser technology.
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29
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Malvestuto M, Ciprian R, Caretta A, Casarin B, Parmigiani F. Ultrafast magnetodynamics with free-electron lasers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:053002. [PMID: 29315080 DOI: 10.1088/1361-648x/aaa211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The study of ultrafast magnetodynamics has entered a new era thanks to the groundbreaking technological advances in free-electron laser (FEL) light sources. The advent of these light sources has made possible unprecedented experimental schemes for time-resolved x-ray magneto-optic spectroscopies, which are now paving the road for exploring the ultimate limits of out-of-equilibrium magnetic phenomena. In particular, these studies will provide insights into elementary mechanisms governing spin and orbital dynamics, therefore contributing to the development of ultrafast devices for relevant magnetic technologies. This topical review focuses on recent advancement in the study of non-equilibrium magnetic phenomena from the perspective of time-resolved extreme ultra violet (EUV) and soft x-ray spectroscopies at FELs with highlights of some important experimental results.
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Affiliation(s)
- Marco Malvestuto
- Elettra-Sincrotrone Trieste S.C.p.A. Strada Statale 14-km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
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30
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Zhang GP, Bai YH, George TF. Is perpendicular magnetic anisotropy essential to all-optical ultrafast spin reversal in ferromagnets? JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:425801. [PMID: 28770812 DOI: 10.1088/1361-648x/aa83c6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
All-optical spin reversal presents a new opportunity for spin manipulations, free of a magnetic field. Most of all-optical-spin-reversal ferromagnets are found to have a perpendicular magnetic anisotropy (PMA), but it has been unknown whether PMA is necessary for spin reversal. Here we theoretically investigate magnetic thin films with either PMA or in-plane magnetic anisotropy (IMA). Our results show that spin reversal in IMA systems is possible, but only with a longer laser pulse and within a narrow laser parameter region. Spin reversal does not show a strong helicity dependence where the left- and right-circularly polarized light lead to the identical results. By contrast, the spin reversal in PMA systems is robust, provided both the spin angular momentum and laser field are strong enough while the magnetic anisotropy itself is not too strong. This explains why experimentally the majority of all-optical spin-reversal samples are found to have strong PMA and why spins in Fe nanoparticles only cant out of plane. It is the laser-induced spin-orbit torque that plays a key role in the spin reversal. Surprisingly, the same spin-orbit torque results in laser-induced spin rectification in spin-mixed configuration, a prediction that can be tested experimentally. Our results clearly point out that PMA is essential to spin reversal, though there is an opportunity for in-plane spin reversal.
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Affiliation(s)
- G P Zhang
- Department of Physics, Indiana State University, Terre Haute, IN 47809, United States of America
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31
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Tang X, Chen S, Lin C, Ding Y. Design of broadband reflective circular polarizer for attosecond pulse in the extreme ultraviolet region. OPTICS EXPRESS 2017; 25:22537-22544. [PMID: 29041562 DOI: 10.1364/oe.25.022537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/18/2017] [Indexed: 06/07/2023]
Abstract
In this paper, we present a design method of broadband reflective circular polarizer (BRCP) in the extreme ultraviolet (EUV) region. By using this method, we designed three BRCPs with a 6, 12 and 18 eV bandwidth, respectively. Then, we investigated the performances of designed BRCPs in theory. The results indicated that the reflected lights of these BRCPs all showed a nearly 100% circular polarization degree and considerable circular reflection in their design band. In addition, we also studied the origin of high circular polarization degree by analyzing the phase shift and the reflectivity ratio between s- and p-polarized lights induced by the reflection of BRCPs. Furthermore, the pulse responses of BRCPs for attosecond pulses were also investigated. The proposed EUV BRCPs can be used for controlling the polarization state of broadband EUV sources, e.g., generating the circularly polarized attosecond pulse by a linearly polarized one.
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32
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Shokeen V, Sanchez Piaia M, Bigot JY, Müller T, Elliott P, Dewhurst JK, Sharma S, Gross EKU. Spin Flips versus Spin Transport in Nonthermal Electrons Excited by Ultrashort Optical Pulses in Transition Metals. PHYSICAL REVIEW LETTERS 2017; 119:107203. [PMID: 28949167 DOI: 10.1103/physrevlett.119.107203] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Indexed: 05/23/2023]
Abstract
A joint theoretical and experimental investigation is performed to understand the underlying physics of laser-induced demagnetization in Ni and Co films with varying thicknesses excited by 10 fs optical pulses. Experimentally, the dynamics of spins is studied by determining the time-dependent amplitude of the Voigt vector, retrieved from a full set of magnetic and nonmagnetic quantities performed on both sides of films, with absolute time reference. Theoretically, ab initio calculations are performed using time-dependent density functional theory. Overall, we demonstrate that spin-orbit induced spin flips are the most significant contributors with superdiffusive spin transport, which assumes only that the transport of majority spins without spin flips induced by scattering does not apply in Ni. In Co it plays a significant role during the first ∼20 fs only. Our study highlights the material dependent nature of the demagnetization during the process of thermalization of nonequilibrium spins.
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Affiliation(s)
- V Shokeen
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67034 Strasbourg, France
| | - M Sanchez Piaia
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67034 Strasbourg, France
| | - J-Y Bigot
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67034 Strasbourg, France
| | - T Müller
- Max-Planck Institut für Microstrukture Physics, Weinberg 2, D-06120 Halle, Germany
| | - P Elliott
- Max-Planck Institut für Microstrukture Physics, Weinberg 2, D-06120 Halle, Germany
| | - J K Dewhurst
- Max-Planck Institut für Microstrukture Physics, Weinberg 2, D-06120 Halle, Germany
| | - S Sharma
- Max-Planck Institut für Microstrukture Physics, Weinberg 2, D-06120 Halle, Germany
| | - E K U Gross
- Max-Planck Institut für Microstrukture Physics, Weinberg 2, D-06120 Halle, Germany
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33
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Buzzi M, Makita M, Howald L, Kleibert A, Vodungbo B, Maldonado P, Raabe J, Jaouen N, Redlin H, Tiedtke K, Oppeneer PM, David C, Nolting F, Lüning J. Single-shot Monitoring of Ultrafast Processes via X-ray Streaking at a Free Electron Laser. Sci Rep 2017; 7:7253. [PMID: 28775262 PMCID: PMC5543111 DOI: 10.1038/s41598-017-07069-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/22/2017] [Indexed: 11/09/2022] Open
Abstract
The advent of x-ray free electron lasers has extended the unique capabilities of resonant x-ray spectroscopy techniques to ultrafast time scales. Here, we report on a novel experimental method that allows retrieving with a single x-ray pulse the time evolution of an ultrafast process, not only at a few discrete time delays, but continuously over an extended time window. We used a single x-ray pulse to resolve the laser-induced ultrafast demagnetisation dynamics in a thin cobalt film over a time window of about 1.6 ps with an excellent signal to noise ratio. From one representative single shot measurement we extract a spin relaxation time of (130 ± 30) fs with an average value, based on 193 single shot events of (113 ± 20) fs. These results are limited by the achieved experimental time resolution of 120 fs, and both values are in excellent agreement with previous results and theoretical modelling. More generally, this new experimental approach to ultrafast x-ray spectroscopy paves the way to the study of non-repetitive processes that cannot be investigated using traditional repetitive pump-probe schemes.
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Affiliation(s)
- Michele Buzzi
- Paul Scherrer Institut, 5232, Villigen PSI, Switzerland.
| | - Mikako Makita
- Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | | | | | - Boris Vodungbo
- Laboratoire d'Optique Appliquée, ENSTA ParisTech - CNRS UMR 7639 École Polytechnique, Chemin de la Hunière, 91761, Palaiseau, France.,Sorbonne Universités, UPMC Univ. Paris 06, CNRS, LCPMR, 75005, Paris, France
| | - Pablo Maldonado
- Department of Physics and Astronomy, Uppsala University, SE-75120, Uppsala, Sweden
| | - Jörg Raabe
- Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif-sur-Yvette Cedex, France
| | - Harald Redlin
- HASYLAB/DESY, Notkestrasse 85, 22607, Hamburg, Germany
| | - Kai Tiedtke
- HASYLAB/DESY, Notkestrasse 85, 22607, Hamburg, Germany
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, SE-75120, Uppsala, Sweden
| | | | | | - Jan Lüning
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, LCPMR, 75005, Paris, France. .,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif-sur-Yvette Cedex, France.
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34
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Measurement of the Resonant Magneto-Optical Kerr Effect Using a Free Electron Laser. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7070662] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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35
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Dynamics of the MnAs α/β-Striped Microstructure and of the Fe Magnetization Reversal in Fe/MnAs/GaAs(001): An Optical-Laser Pump–Free-Electron-Laser Probe Scattering Experiment. PHOTONICS 2017. [DOI: 10.3390/photonics4020021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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Jana S, Terschlüsen JA, Stefanuik R, Plogmaker S, Troisi S, Malik RS, Svanqvist M, Knut R, Söderström J, Karis O. A setup for element specific magnetization dynamics using the transverse magneto-optic Kerr effect in the energy range of 30-72 eV. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:033113. [PMID: 28372391 DOI: 10.1063/1.4978907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper, we present a spectrometer that is designed for element-specific and time-resolved transverse magneto-optic Kerr effect experiments at the high-harmonic generation pump-probe facility High Energy Laser Induced Overtone Source (HELIOS) laboratory. HELIOS delivers photons with energies between 30 eV and 72 eV with an overall time resolution of less than 40 fs. The spectrometer is based on a Rowland-circle geometry and allows for simultaneous measurements of all magnetic transition-metal elements. The setup also features easy sample transfer and alignment, and it combines high photon throughput, optimized data acquisition, and a fast switching of the magnetic field at the sample. The spectrometer performance is demonstrated by measuring the ultrafast demagnetization of permalloy. Our data are, for all practical purposes, identical to what have been reported in the earlier high-order harmonic generation work of a similar sample by Mathias et al. [Proc. Natl. Acad. Sci. U. S. A. 109, 4792-4797 (2012)], however, obtained within 15% of the acquisition time compared to their study. Furthermore, our data show a shift of the demagnetization curve of Ni relative to Fe, which has previously been interpreted as a delay of the Ni demagnetization to that of Fe [S. Mathias et al., Proc. Natl. Acad. Sci. U. S. A. 109, 4792-4797 (2012)].
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Affiliation(s)
- S Jana
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - J A Terschlüsen
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - R Stefanuik
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - S Plogmaker
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - S Troisi
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - R S Malik
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - M Svanqvist
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - R Knut
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - J Söderström
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
| | - O Karis
- Department of Physics and Astronomy, Molecular and Condensed Matter Physics, Uppsala University, P.O. Box 516, 75120 Uppsala, Sweden
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37
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Neville SP, Averbukh V, Ruberti M, Yun R, Patchkovskii S, Chergui M, Stolow A, Schuurman MS. Excited state X-ray absorption spectroscopy: Probing both electronic and structural dynamics. J Chem Phys 2016; 145:144307. [DOI: 10.1063/1.4964369] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Simon P. Neville
- Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, ISIC, Lausanne CH-1015, Switzerland
| | - Vitali Averbukh
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Marco Ruberti
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Renjie Yun
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | | | - Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, ISIC, Lausanne CH-1015, Switzerland
| | - Albert Stolow
- Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Michael S. Schuurman
- Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
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Zhang K, Lin MF, Ryland ES, Verkamp MA, Benke K, de Groot FMF, Girolami GS, Vura-Weis J. Shrinking the Synchrotron: Tabletop Extreme Ultraviolet Absorption of Transition-Metal Complexes. J Phys Chem Lett 2016; 7:3383-7. [PMID: 27513100 DOI: 10.1021/acs.jpclett.6b01393] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We show that the electronic structure of molecular first-row transition-metal complexes can be reliably measured using tabletop high-harmonic XANES at the metal M2,3 edge. Extreme ultraviolet photons in the 50-70 eV energy range probe 3p → 3d transitions, with the same selection rules as soft X-ray L2,3-edge absorption (2p → 3d excitation). Absorption spectra of model complexes are sensitive to the electronic structure of the metal center, and ligand field multiplet simulations match the shapes and peak-to-peak spacings of the experimental spectra. This work establishes high-harmonic spectroscopy as a powerful tool for studying the electronic structure of molecular inorganic, bioinorganic, and organometallic compounds.
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Affiliation(s)
- Kaili Zhang
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
| | - Ming-Fu Lin
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
| | - Elizabeth S Ryland
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
| | - Max A Verkamp
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
| | - Kristopher Benke
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
| | - Frank M F de Groot
- Department of Chemistry, Utrecht University , 3584 CG Utrecht, The Netherlands
| | - Gregory S Girolami
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
| | - Josh Vura-Weis
- Department of Chemistry, University of Illinois at Urbana-Champaign , Champaign 61801, United States
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39
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Chen ZY, Pukhov A. Bright high-order harmonic generation with controllable polarization from a relativistic plasma mirror. Nat Commun 2016; 7:12515. [PMID: 27531047 PMCID: PMC4992059 DOI: 10.1038/ncomms12515] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 07/11/2016] [Indexed: 11/09/2022] Open
Abstract
Ultrafast extreme ultraviolet (XUV) sources with a controllable polarization state are powerful tools for investigating the structural and electronic as well as the magnetic properties of materials. However, such light sources are still limited to only a few free-electron laser facilities and, very recently, to high-order harmonic generation from noble gases. Here we propose and numerically demonstrate a laser-plasma scheme to generate bright XUV pulses with fully controlled polarization. In this scheme, an elliptically polarized laser pulse is obliquely incident on a plasma surface, and the reflected radiation contains pulse trains and isolated circularly or highly elliptically polarized attosecond XUV pulses. The harmonic polarization state is fully controlled by the laser-plasma parameters. The mechanism can be explained within the relativistically oscillating mirror model. This scheme opens a practical and promising route to generate bright attosecond XUV pulses with desirable ellipticities in a straightforward and efficient way for a number of applications.
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Affiliation(s)
- Zi-Yu Chen
- Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, Düsseldorf D-40225, Germany
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621999, China
| | - Alexander Pukhov
- Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, Düsseldorf D-40225, Germany
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40
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Plötzing M, Adam R, Weier C, Plucinski L, Eich S, Emmerich S, Rollinger M, Aeschlimann M, Mathias S, Schneider CM. Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:043903. [PMID: 27131684 DOI: 10.1063/1.4946782] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The fundamental mechanism responsible for optically induced magnetization dynamics in ferromagnetic thin films has been under intense debate since almost two decades. Currently, numerous competing theoretical models are in strong need for a decisive experimental confirmation such as monitoring the triggered changes in the spin-dependent band structure on ultrashort time scales. Our approach explores the possibility of observing femtosecond band structure dynamics by giving access to extended parts of the Brillouin zone in a simultaneously time-, energy- and spin-resolved photoemission experiment. For this purpose, our setup uses a state-of-the-art, highly efficient spin detector and ultrashort, extreme ultraviolet light pulses created by laser-based high-order harmonic generation. In this paper, we present the setup and first spin-resolved spectra obtained with our experiment within an acquisition time short enough to allow pump-probe studies. Further, we characterize the influence of the excitation with femtosecond extreme ultraviolet pulses by comparing the results with data acquired using a continuous wave light source with similar photon energy. In addition, changes in the spectra induced by vacuum space-charge effects due to both the extreme ultraviolet probe- and near-infrared pump-pulses are studied by analyzing the resulting spectral distortions. The combination of energy resolution and electron count rate achieved in our setup confirms its suitability for spin-resolved studies of the band structure on ultrashort time scales.
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Affiliation(s)
- M Plötzing
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - R Adam
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - C Weier
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - L Plucinski
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
| | - S Eich
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - S Emmerich
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - M Rollinger
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - M Aeschlimann
- University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern, Germany
| | - S Mathias
- Georg-August-Universität Göttingen, I. Physikalisches Institut, 37077 Göttingen, Germany
| | - C M Schneider
- Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich, Germany
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41
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Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering. Nat Commun 2016; 7:10343. [PMID: 26757813 PMCID: PMC4735510 DOI: 10.1038/ncomms10343] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/03/2015] [Indexed: 11/28/2022] Open
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.
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42
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Neville SP, Averbukh V, Patchkovskii S, Ruberti M, Yun R, Chergui M, Stolow A, Schuurman MS. Beyond structure: ultrafast X-ray absorption spectroscopy as a probe of non-adiabatic wavepacket dynamics. Faraday Discuss 2016; 194:117-145. [DOI: 10.1039/c6fd00117c] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The excited state non-adiabatic dynamics of polyatomic molecules, leading to the coupling of structural and electronic dynamics, is a fundamentally important yet challenging problem for both experiment and theory. Ongoing developments in ultrafast extreme vacuum ultraviolet (XUV) and soft X-ray sources present new probes of coupled electronic-structural dynamics because of their novel and desirable characteristics. As one example, inner-shell spectroscopy offers localized, atom-specific probes of evolving electronic structure and bonding (via chemical shifts). In this work, we present the first on-the-fly ultrafast X-ray time-resolved absorption spectrum simulations of excited state wavepacket dynamics: photo-excited ethylene. This was achieved by coupling the ab initio multiple spawning (AIMS) method, employing on-the-fly dynamics simulations, with high-level algebraic diagrammatic construction (ADC) X-ray absorption cross-section calculations. Using the excited state dynamics of ethylene as a test case, we assessed the ability of X-ray absorption spectroscopy to project out the electronic character of complex wavepacket dynamics, and evaluated the sensitivity of the calculated spectra to large amplitude nuclear motion. In particular, we demonstrate the pronounced sensitivity of the pre-edge region of the X-ray absorption spectrum to the electronic and structural evolution of the excited-state wavepacket. We conclude that ultrafast time-resolved X-ray absorption spectroscopy may become a powerful tool in the interrogation of excited state non-adiabatic molecular dynamics.
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Affiliation(s)
| | - Vitali Averbukh
- Department of Physics
- Imperial College London
- South Kensington Campus
- London
- UK
| | | | - Marco Ruberti
- Department of Physics
- Imperial College London
- South Kensington Campus
- London
- UK
| | - Renjie Yun
- Department of Physics
- Imperial College London
- South Kensington Campus
- London
- UK
| | - Majed Chergui
- École Polytechnique Fédérale de Lausanne
- Laboratoire de Spectroscopie Ultrarapide and Lausanne Centre for Ultrafast Science (LACUS)
- Faculté des Sciences de Base
- ISIC
- Lausanne CH-1015
| | - Albert Stolow
- Department of Chemistry
- University of Ottawa
- Ottawa
- Canada
- National Research Council of Canada
| | - Michael S. Schuurman
- Department of Chemistry
- University of Ottawa
- Ottawa
- Canada
- National Research Council of Canada
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43
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Svetina C, Mahne N, Raimondi L, Caretta A, Casarin B, Dell'Angela M, Malvestuto M, Parmigiani F, Zangrando M. MagneDyn: the beamline for magneto dynamics studies at FERMI. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:98-105. [PMID: 26698050 DOI: 10.1107/s1600577515022080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/18/2015] [Indexed: 06/05/2023]
Abstract
The future Magneto Dynamics (MagneDyn) beamline will be devoted to study the electronic states and the local magnetic properties of excited and transient states of complex systems by means of the time-resolved X-ray absorption spectroscopy technique. The beamline will use FERMI's high-energy source covering the wavelength range from 60 nm down to 1.3 nm. An on-line photon energy spectrometer will allow spectra to be measured with high resolution while delivering most of the beam to the end-stations. Downstream the beam will be possibly split and delayed, by means of a delay line, and then focused with a set of active Kirkpatrick-Baez mirrors. These mirrors will be able to focus the radiation in one of the two MagneDyn experimental chambers: the electromagnet end-station and the resonant inelastic X-ray scattering end-station. After an introduction of the MagneDyn scientific case, the layout will be discussed showing the expected performances of the beamline.
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Affiliation(s)
- Cristian Svetina
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Nicola Mahne
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Lorenzo Raimondi
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Antonio Caretta
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Barbara Casarin
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Martina Dell'Angela
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Marco Malvestuto
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Fulvio Parmigiani
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
| | - Marco Zangrando
- Elettra-Sincrotrone Trieste SCpA, SS 14 km 163.5 in Area Science Park, 34149 Basovizza, Italy
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44
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Schmidt J, Guggenmos A, Hofstetter M, Chew SH, Kleineberg U. Generation of circularly polarized high harmonic radiation using a transmission multilayer quarter waveplate. OPTICS EXPRESS 2015; 23:33564-33578. [PMID: 26832020 DOI: 10.1364/oe.23.033564] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
High harmonic radiation is meanwhile nearly extensively used for the spectroscopic investigation of electron dynamics with ultimate time resolution. The majority of high harmonic beamlines provide linearly polarized radiation created in a gas target. However, circular polarization greatly extends the spectroscopic possibilities for high harmonics, especially in the analysis of samples with chirality or prominent spin polarization. We produced a free-standing multilayer foil as a transmission EUV quarter waveplate and applied it for the first time to high harmonic radiation. We measured a broadband (4.6 eV FWHM) ellipticity of 75% at 66 eV photon energy with a transmission efficiency of 5%. The helicity is switchable and the ellipticity can be adjusted to lower values by angle tuning. As a single element it can be easily integrated in any existing harmonic beamline without major changes.
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45
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Fischer P, Ohldag H. X-rays and magnetism. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:094501. [PMID: 26288956 DOI: 10.1088/0034-4885/78/9/094501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Magnetism is among the most active and attractive areas in modern solid state physics because of intriguing phenomena interesting to fundamental research and a manifold of technological applications. State-of-the-art synthesis of advanced magnetic materials, e.g. in hybrid structures paves the way to new functionalities. To characterize modern magnetic materials and the associated magnetic phenomena, polarized x-rays have emerged as unique probes due to their specific interaction with magnetic materials. A large variety of spectroscopic and microscopic techniques have been developed to quantify in an element, valence and site-sensitive way properties of ferro-, ferri-, and antiferromagnetic systems, such as spin and orbital moments, and to image nanoscale spin textures and their dynamics with sub-ns time and almost 10 nm spatial resolution. The enormous intensity of x-rays and their degree of coherence at next generation x-ray facilities will open the fsec time window to magnetic studies addressing fundamental time scales in magnetism with nanometer spatial resolution. This review will give an introduction into contemporary topics of nanoscale magnetic materials and provide an overview of analytical spectroscopy and microscopy tools based on x-ray dichroism effects. Selected examples of current research will demonstrate the potential and future directions of these techniques.
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Affiliation(s)
- Peter Fischer
- Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, USA. Physics Department, University of California Santa Cruz, 1156 High St, Santa Cruz, CA 94056, USA
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46
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Self Referencing Heterodyne Transient Grating Spectroscopy with Short Wavelength. PHOTONICS 2015. [DOI: 10.3390/photonics2020392] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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47
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Sistrunk E, Grilj J, Jeong J, Samant MG, Gray AX, Dürr HA, Parkin SSP, Gühr M. Broadband extreme ultraviolet probing of transient gratings in vanadium dioxide. OPTICS EXPRESS 2015; 23:4340-4347. [PMID: 25836470 DOI: 10.1364/oe.23.004340] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nonlinear spectroscopy in the extreme ultraviolet (EUV) and soft x-ray spectral range offers the opportunity for element selective probing of ultrafast dynamics using core-valence transitions (Mukamel et al., Acc. Chem. Res. 42, 553 (2009)). We demonstrate a step on this path showing core-valence sensitivity in transient grating spectroscopy with EUV probing. We study the optically induced insulator-to-metal transition (IMT) of a VO(2) film with EUV diffraction from the optically excited sample. The VO(2) exhibits a change in the 3p-3d resonance of V accompanied by an acoustic response. Due to the broadband probing we are able to separate the two features.
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48
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Spezzani C, Ferrari E, Allaria E, Vidal F, Ciavardini A, Delaunay R, Capotondi F, Pedersoli E, Coreno M, Svetina C, Raimondi L, Zangrando M, Ivanov R, Nikolov I, Demidovich A, Danailov MB, Popescu H, Eddrief M, De Ninno G, Kiskinova M, Sacchi M. Magnetization and microstructure dynamics in Fe/MnAs/GaAs(001): Fe magnetization reversal by a femtosecond laser pulse. PHYSICAL REVIEW LETTERS 2014; 113:247202. [PMID: 25541801 DOI: 10.1103/physrevlett.113.247202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Indexed: 06/04/2023]
Abstract
Thin film magnetization reversal without applying external fields is an attractive perspective for applications in sensors and devices. One way to accomplish it is by fine-tuning the microstructure of a magnetic substrate via temperature control, as in the case of a thin Fe layer deposited on a MnAs/GaAs(001) template. This work reports a time-resolved resonant scattering study exploring the magnetic and structural properties of the Fe/MnAs system, using a 100 fs optical laser pulse to trigger local temperature variations and a 100 fs x-ray free-electron laser pulse to probe the induced magnetic and structural dynamics. The experiment provides direct evidence that a single optical laser pulse can reverse the Fe magnetization locally. It reveals that the time scale of the magnetization reversal is slower than that of the MnAs structural transformations triggered by the optical pulse, which take place after a few picoseconds already.
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Affiliation(s)
- C Spezzani
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - E Ferrari
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy and Dipartimento di Fisica, Università degli Studi di Trieste, 34127 Trieste, Italy
| | - E Allaria
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - F Vidal
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7588, INSP, F-75005 Paris, France and CNRS, UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - A Ciavardini
- CNR-ISM, via Salaria km 29, 300-00016 Monterotondo Scalo (RM), Italy
| | - R Delaunay
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, LCPMR, F-75005 Paris, France and CNRS, UMR 7614, LCPMR, F-75005 Paris, France
| | - F Capotondi
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - E Pedersoli
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - M Coreno
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy and CNR-ISM, via Salaria km 29, 300-00016 Monterotondo Scalo (RM), Italy
| | - C Svetina
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy and Graduate School of Nanotechnology, University of Trieste, 34127 Trieste, Italy
| | - L Raimondi
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - M Zangrando
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - R Ivanov
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - I Nikolov
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - A Demidovich
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - M B Danailov
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - H Popescu
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, France
| | - M Eddrief
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7588, INSP, F-75005 Paris, France and CNRS, UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - G De Ninno
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy and Laboratory of Quantum Optics, University of Nova Gorica, 5001 Nova Gorica, Slovenia
| | - M Kiskinova
- ELETTRA-Sincrotrone Trieste, 34149 Trieste, Italy
| | - M Sacchi
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7588, INSP, F-75005 Paris, France and CNRS, UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France and Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, France
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49
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van der Laan G, Figueroa AI. X-ray magnetic circular dichroism—A versatile tool to study magnetism. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.03.018] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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50
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Grazioli C, Callegari C, Ciavardini A, Coreno M, Frassetto F, Gauthier D, Golob D, Ivanov R, Kivimäki A, Mahieu B, Bučar B, Merhar M, Miotti P, Poletto L, Polo E, Ressel B, Spezzani C, De Ninno G. CITIUS: an infrared-extreme ultraviolet light source for fundamental and applied ultrafast science. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:023104. [PMID: 24593346 DOI: 10.1063/1.4864298] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We present the main features of CITIUS, a new light source for ultrafast science, generating tunable, intense, femtosecond pulses in the spectral range from infrared to extreme ultraviolet (XUV). The XUV pulses (about 10(5)-10(8) photons/pulse in the range 14-80 eV) are produced by laser-induced high-order harmonic generation in gas. This radiation is monochromatized by a time-preserving monochromator, also allowing one to work with high-resolution bandwidth selection. The tunable IR-UV pulses (10(12)-10(15) photons/pulse in the range 0.4-5.6 eV) are generated by an optical parametric amplifier, which is driven by a fraction of the same laser pulse that generates high order harmonics. The IR-UV and XUV pulses follow different optical paths and are eventually recombined on the sample for pump-probe experiments. We also present the results of two pump-probe experiments: with the first one, we fully characterized the temporal duration of harmonic pulses in the time-preserving configuration; with the second one, we demonstrated the possibility of using CITIUS for selective investigation of the ultra-fast dynamics of different elements in a magnetic compound.
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Affiliation(s)
- C Grazioli
- Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia
| | | | | | - M Coreno
- Elettra Sincrotrone Trieste, Trieste, Italy
| | - F Frassetto
- Institute of Photonics and Nanotechnologies (CNR-IFN), Padova, Italy
| | - D Gauthier
- Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia
| | - D Golob
- Kontrolni Sistemi d.o.o., Sežana, Slovenia
| | - R Ivanov
- Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia
| | - A Kivimäki
- Institute of Materials Manufacturing (CNR-IOM), TASC Laboratory, Trieste, Italy
| | - B Mahieu
- Elettra Sincrotrone Trieste, Trieste, Italy
| | - B Bučar
- Laboratory of Mechanical Processing Technologies, University of Ljubljana, Ljubljana, Slovenia
| | - M Merhar
- Laboratory of Mechanical Processing Technologies, University of Ljubljana, Ljubljana, Slovenia
| | - P Miotti
- Institute of Photonics and Nanotechnologies (CNR-IFN), Padova, Italy
| | - L Poletto
- Institute of Photonics and Nanotechnologies (CNR-IFN), Padova, Italy
| | - E Polo
- Institute of Organic Synthesis and Photoreactivity (CNR-ISOF), Ferrara, Italy
| | - B Ressel
- Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia
| | - C Spezzani
- Elettra Sincrotrone Trieste, Trieste, Italy
| | - G De Ninno
- Laboratory of Quantum Optics, University of Nova Gorica, Nova Gorica, Slovenia
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