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Tanikawa T, Karabekyan S, Kovalev S, Casalbuoni S, Asgekar V, Bonetti S, Wall S, Laarmann T, Turchinovich D, Zalden P, Kampfrath T, Fisher AS, Stojanovic N, Gensch M, Geloni G. Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers. J Synchrotron Radiat 2020; 27:796-798. [PMID: 32381783 PMCID: PMC7206546 DOI: 10.1107/s1600577520004245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Å-1 and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure.
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Affiliation(s)
- T. Tanikawa
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - S. Karabekyan
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - S. Kovalev
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - S. Casalbuoni
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - V. Asgekar
- Physics Department, S. P. Pune University, Pune 411 007, India
| | - S. Bonetti
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
- Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, 30172 Venice, Italy
| | - S. Wall
- ICFO, Avinguda Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain
| | - T. Laarmann
- Deutsches Elektronen Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging CUI, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - D. Turchinovich
- Fakultät für Physik, Universität Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - P. Zalden
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - T. Kampfrath
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - A. S. Fisher
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - N. Stojanovic
- Deutsches Elektronen Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- DLR – Institute for Optical Sensor Systems, Rutherfordstraße 2, 12489 Berlin, Germany
| | - M. Gensch
- DLR – Institute for Optical Sensor Systems, Rutherfordstraße 2, 12489 Berlin, Germany
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Straße des 17 Juni 135, 10623 Berlin, Germany
| | - G. Geloni
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
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D'Angelo F, Němec H, Parekh SH, Kužel P, Bonn M, Turchinovich D. Self-referenced ultra-broadband transient terahertz spectroscopy using air-photonics. Opt Express 2016; 24:10157-10171. [PMID: 27137624 DOI: 10.1364/oe.24.010157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Terahertz (THz) air-photonics employs nonlinear interactions of ultrashort laser pulses in air to generate and detect THz pulses. As air is virtually non-dispersive, the optical-THz phase matching condition is automatically met, thus permitting the generation and detection of ultra-broadband THz pulses covering the entire THz spectral range without any gaps. Air-photonics naturally offers unique opportunities for ultra-broadband transient THz spectroscopy, yet many critical challenges inherent to this technique must first be resolved. Here, we present explicit guidelines for ultra-broadband transient THz spectroscopy with air-photonics, including a novel method for self-referenced signal acquisition minimizing the phase error, and the numerically-accurate approach to the transient reflectance data analysis.
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Jensen SA, Mics Z, Ivanov I, Varol HS, Turchinovich D, Koppens FHL, Bonn M, Tielrooij KJ. Competing ultrafast energy relaxation pathways in photoexcited graphene. Nano Lett 2014; 14:5839-45. [PMID: 25247639 DOI: 10.1021/nl502740g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
For most optoelectronic applications of graphene, a thorough understanding of the processes that govern energy relaxation of photoexcited carriers is essential. The ultrafast energy relaxation in graphene occurs through two competing pathways: carrier-carrier scattering, creating an elevated carrier temperature, and optical phonon emission. At present, it is not clear what determines the dominating relaxation pathway. Here we reach a unifying picture of the ultrafast energy relaxation by investigating the terahertz photoconductivity, while varying the Fermi energy, photon energy and fluence over a wide range. We find that sufficiently low fluence (≲4 μJ/cm(2)) in conjunction with sufficiently high Fermi energy (≳0.1 eV) gives rise to energy relaxation that is dominated by carrier-carrier scattering, which leads to efficient carrier heating. Upon increasing the fluence or decreasing the Fermi energy, the carrier heating efficiency decreases, presumably due to energy relaxation that becomes increasingly dominated by phonon emission. Carrier heating through carrier-carrier scattering accounts for the negative photoconductivity for doped graphene observed at terahertz frequencies. We present a simple model that reproduces the data for a wide range of Fermi levels and excitation energies and allows us to qualitatively assess how the branching ratio between the two distinct relaxation pathways depends on excitation fluence and Fermi energy.
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Affiliation(s)
- S A Jensen
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
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Liu X, Lægsgaard J, Møller U, Tu H, Boppart SA, Turchinovich D. All-fiber femtosecond Cherenkov source. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134110017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Turchinovich D, Hvam JM, Hoffmann MC. Self-phase modulation of a single-cycle THz pulse. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134109003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tu H, Liu Y, Lægsgaard J, Turchinovich D, Siegel M, Kopf D, Li H, Gunaratne T, Boppart S. Cross-validation of theoretically quantified fiber continuum generation and absolute pulse measurement by MIIPS for a broadband coherently controlled optical source. Appl Phys B 2012; 106:379-384. [PMID: 23144537 PMCID: PMC3491074 DOI: 10.1007/s00340-011-4746-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The predicted spectral phase of a fiber continuum pulsed source rigorously quantified by the scalar generalized nonlinear Schrödinger equation is found to be in excellent agreement with that measured by multiphoton intra-pulse interference phase scan (MIIPS) with background subtraction. This cross-validation confirms the absolute pulse measurement by MIIPS and the transform-limited compression of the fiber continuum pulses by the pulse shaper performing the MIIPS measurement, and permits the subsequent coherent control on the fiber continuum pulses by this pulse shaper. The combination of the fiber continuum source with the MIIPS-integrated pulse shaper produces compressed transform-limited 9.6 fs (FWHM) pulses or arbitrarily shaped pulses at a central wavelength of 1020 nm, an average power over 100 mW, and a repetition rate of 76 MHz. In comparison to the 229-fs pump laser pulses that generate the fiber continuum, the compressed pulses reflect a compression ratio of 24.
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Affiliation(s)
- H. Tu
- Biophotonics Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Y. Liu
- Biophotonics Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - J. Lægsgaard
- DTU Fotonik—Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - D. Turchinovich
- DTU Fotonik—Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - M. Siegel
- High Q Laser Innovation GmbH, Feldgut 9, 6830 Rankweil, Austria
| | - D. Kopf
- High Q Laser Innovation GmbH, Feldgut 9, 6830 Rankweil, Austria
| | - H. Li
- BioPhotonics Solutions, Inc., 1401 East Lansing Drive, Suite 112, East Lansing, MI 48823, USA
| | - T. Gunaratne
- BioPhotonics Solutions, Inc., 1401 East Lansing Drive, Suite 112, East Lansing, MI 48823, USA
| | - S.A. Boppart
- Biophotonics Imaging Laboratory, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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