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Oelmann JH, Guth L, Heldt T, Griesbach N, Hector R, Lackmann N, Nauta J, Pfeifer T, Crespo López-Urrutia JR. Closed-cycle noble gas recycling system for high-repetition rate high-harmonic generation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:035115. [PMID: 38477653 DOI: 10.1063/5.0176563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/20/2024] [Indexed: 03/14/2024]
Abstract
We present a compact closed-loop recycling system for noble and inert gases. It has been developed for an extreme-ultraviolet (XUV) frequency comb based on high-harmonic generation at 100 MHz repetition rate. The system collects gas injected at several bars of backing pressure through a micrometer-sized nozzle into the laser-interaction region with a differential pumping system comprising turbomolecular pumps, and subsequently compresses the gas to a pressure of up to 200 bar. By drastically reducing the waste of expensive gases such as xenon and krypton, it enables the long operation times needed for spectroscopic measurements, as well as for continuous operation of the XUV frequency comb.
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Magunia A, Rebholz M, Appi E, Papadopoulou CC, Lindenblatt H, Trost F, Meister S, Ding T, Straub M, Borisova GD, Lee J, Jin R, von der Dellen A, Kaiser C, Braune M, Düsterer S, Ališauskas S, Lang T, Heyl C, Manschwetus B, Grunewald S, Frühling U, Tajalli A, Wahid AB, Silletti L, Calegari F, Mosel P, Morgner U, Kovacev M, Thumm U, Hartl I, Treusch R, Moshammer R, Ott C, Pfeifer T. Time-resolving state-specific molecular dissociation with XUV broadband absorption spectroscopy. SCIENCE ADVANCES 2023; 9:eadk1482. [PMID: 37992169 PMCID: PMC10664994 DOI: 10.1126/sciadv.adk1482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/24/2023] [Indexed: 11/24/2023]
Abstract
The electronic and nuclear dynamics inside molecules are essential for chemical reactions, where different pathways typically unfold on ultrafast timescales. Extreme ultraviolet (XUV) light pulses generated by free-electron lasers (FELs) allow atomic-site and electronic-state selectivity, triggering specific molecular dynamics while providing femtosecond resolution. Yet, time-resolved experiments are either blind to neutral fragments or limited by the spectral bandwidth of FEL pulses. Here, we combine a broadband XUV probe pulse from high-order harmonic generation with an FEL pump pulse to observe dissociation pathways leading to fragments in different quantum states. We temporally resolve the dissociation of a specific O2+ state into two competing channels by measuring the resonances of ionic and neutral fragments. This scheme can be applied to investigate convoluted dynamics in larger molecules relevant to diverse science fields.
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Rupprecht P, Magunia A, Aufleger L, Ott C, Pfeifer T. Flexible experimental platform for dispersion-free temporal characterization of ultrashort pulses. OPTICS EXPRESS 2023; 31:39821-39831. [PMID: 38041296 DOI: 10.1364/oe.503731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/17/2023] [Indexed: 12/03/2023]
Abstract
The precise temporal characterization of laser pulses is crucial for ultrashort applications in biology, chemistry, and physics. Especially in femto- and attosecond science, diverse laser pulse sources in different spectral regimes from the visible to the infrared as well as pulse durations ranging from picoseconds to few femtoseconds are employed. In this article, we present a versatile temporal-characterization apparatus that can access these different temporal and spectral regions in a dispersion-free manner and without phase-matching constraints. The design combines transient-grating and surface third-harmonic-generation frequency-resolved optical gating in one device with optimized alignment capabilities based on a noncollinear geometry.
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4
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Rehbehn NH, Rosner MK, Berengut JC, Schmidt PO, Pfeifer T, Gu MF, López-Urrutia JRC. Narrow and Ultranarrow Transitions in Highly Charged Xe Ions as Probes of Fifth Forces. PHYSICAL REVIEW LETTERS 2023; 131:161803. [PMID: 37925712 DOI: 10.1103/physrevlett.131.161803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 07/21/2023] [Accepted: 09/15/2023] [Indexed: 11/07/2023]
Abstract
Optical frequency metrology in atoms and ions can probe hypothetical fifth forces between electrons and neutrons by sensing minute perturbations of the electronic wave function induced by them. A generalized King plot has been proposed to distinguish them from possible standard model effects arising from, e.g., finite nuclear size and electronic correlations. Additional isotopes and transitions are required for this approach. Xenon is an excellent candidate, with seven stable isotopes with zero nuclear spin, however it has no known visible ground-state transitions for high resolution spectroscopy. To address this, we have found and measured twelve magnetic-dipole lines in its highly charged ions and theoretically studied their sensitivity to fifth forces as well as the suppression of spurious higher-order standard model effects. Moreover, we identified at 764.8753(16) nm a E2-type ground-state transition with 500 s excited state lifetime as a potential clock candidate further enhancing our proposed scheme.
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Ertel D, Busto D, Makos I, Schmoll M, Benda J, Ahmadi H, Moioli M, Frassetto F, Poletto L, Schröter CD, Pfeifer T, Moshammer R, Mašín Z, Patchkovskii S, Sansone G. Influence of nuclear dynamics on molecular attosecond photoelectron interferometry. SCIENCE ADVANCES 2023; 9:eadh7747. [PMID: 37647394 PMCID: PMC10468127 DOI: 10.1126/sciadv.adh7747] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 07/19/2023] [Indexed: 09/01/2023]
Abstract
In extreme ultraviolet spectroscopy, the photoionization process occurring in a molecule due to the absorption of a single photon can trigger an ultrafast nuclear motion in the cation. Taking advantage of attosecond photoelectron interferometry, where the absorption of the extreme ultraviolet photon is accompanied by the exchange of an additional infrared quantum of light, one can investigate the influence of nuclear dynamics by monitoring the characteristics of the photoelectron spectra generated by the two-color field. Here, we show that attosecond photoelectron interferometry is sensitive to the nuclear response by measuring the two-color photoionization spectra in a mixture of methane (CH4) and deuteromethane (CD4). The effect of the different nuclear evolution in the two isotopologues manifests itself in the modification of the amplitude and contrast of the oscillations of the photoelectron peaks. Our work indicates that nuclear dynamics can affect the coherence properties of the electronic wave packet emitted by photoionization on a time scale as short as a few femtoseconds.
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Guillemin R, Inhester L, Ilchen M, Mazza T, Boll R, Weber T, Eckart S, Grychtol P, Rennhack N, Marchenko T, Velasquez N, Travnikova O, Ismail I, Niskanen J, Kukk E, Trinter F, Gisselbrecht M, Feifel R, Sansone G, Rolles D, Martins M, Meyer M, Simon M, Santra R, Pfeifer T, Jahnke T, Piancastelli MN. Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2023; 10:054302. [PMID: 37799711 PMCID: PMC10550338 DOI: 10.1063/4.0000197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 09/05/2023] [Indexed: 10/07/2023]
Abstract
Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we identify significant structural dynamics with characteristic isotope effects in H2O2+, D2O2+, and HDO2+, such as asymmetric bond elongation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. A method to disentangle the sequences of events taking place upon the consecutive absorption of two x-ray photons is described. The obtained deep look into structural properties and dynamics of dissociating water isotopologues provides essential insights into the underlying mechanisms.
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7
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Schnorr K, Belina M, Augustin S, Lindenblatt H, Liu Y, Meister S, Pfeifer T, Schmid G, Treusch R, Trost F, Slavíˇek P, Moshammer R. Direct tracking of ultrafast proton transfer in water dimers. SCIENCE ADVANCES 2023; 9:eadg7864. [PMID: 37436977 PMCID: PMC10337913 DOI: 10.1126/sciadv.adg7864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/08/2023] [Indexed: 07/14/2023]
Abstract
Upon ionization, water forms a highly acidic radical cation H2O+· that undergoes ultrafast proton transfer (PT)-a pivotal step in water radiation chemistry, initiating the production of reactive H3O+, OH[Formula: see text] radicals, and a (hydrated) electron. Until recently, the time scales, mechanisms, and state-dependent reactivity of ultrafast PT could not be directly traced. Here, we investigate PT in water dimers using time-resolved ion coincidence spectroscopy applying a free-electron laser. An extreme ultraviolet (XUV) pump photon initiates PT, and only dimers that have undergone PT at the instance of the ionizing XUV probe photon result in distinct H3O+ + OH+ pairs. By tracking the delay-dependent yield and kinetic energy release of these ion pairs, we measure a PT time of (55 ± 20) femtoseconds and image the geometrical rearrangement of the dimer cations during and after PT. Our direct measurement shows good agreement with nonadiabatic dynamics simulations for the initial PT and allows us to benchmark nonadiabatic theory.
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8
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Ertel D, Schmoll M, Kellerer S, Jäger A, Weissenbilder R, Moioli M, Ahmadi H, Busto D, Makos I, Frassetto F, Poletto L, Schröter CD, Pfeifer T, Moshammer R, Sansone G. Ultrastable, high-repetition-rate attosecond beamline for time-resolved XUV-IR coincidence spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:073001. [PMID: 37404094 DOI: 10.1063/5.0139496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 05/30/2023] [Indexed: 07/06/2023]
Abstract
The implementation of attosecond photoelectron-photoion coincidence spectroscopy for the investigation of atomic and molecular dynamics calls for a high-repetition-rate driving source combined with experimental setups characterized by excellent stability for data acquisition over time intervals ranging from a few hours up to a few days. This requirement is crucial for the investigation of processes characterized by low cross sections and for the characterization of fully differential photoelectron(s) and photoion(s) angular and energy distributions. We demonstrate that the implementation of industrial-grade lasers, combined with a careful design of the delay line implemented in the pump-probe setup, allows one to reach ultrastable experimental conditions leading to an error in the estimation of the time delays of only 12 as over an acquisition time of 6.5 h. This result opens up new possibilities for the investigation of attosecond dynamics in simple quantum systems.
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Heldt T, Dubois J, Birk P, Borisova GD, Lando GM, Ott C, Pfeifer T. Attosecond Real-Time Observation of Recolliding Electron Trajectories in Helium at Low Laser Intensities. PHYSICAL REVIEW LETTERS 2023; 130:183201. [PMID: 37204888 DOI: 10.1103/physrevlett.130.183201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/20/2023] [Accepted: 03/16/2023] [Indexed: 05/21/2023]
Abstract
Laser-driven recollision physics is typically accessible only at field intensities high enough for tunnel ionization. Using an extreme ultraviolet pulse for ionization and a near-infrared (NIR) pulse for driving of the electron wave packet lifts this limitation. This allows us to study recollisions for a broad range of NIR intensities with transient absorption spectroscopy, making use of the reconstruction of the time-dependent dipole moment. Comparing recollision dynamics with linear vs circular NIR polarization, we find a parameter space, where the latter favors recollisions, providing evidence for the so far only theoretically predicted recolliding periodic orbits.
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10
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Wang E, Kling NG, LaForge AC, Obaid R, Pathak S, Bhattacharyya S, Meister S, Trost F, Lindenblatt H, Schoch P, Kübel M, Pfeifer T, Rudenko A, Díaz-Tendero S, Martín F, Moshammer R, Rolles D, Berrah N. Ultrafast Roaming Mechanisms in Ethanol Probed by Intense Extreme Ultraviolet Free-Electron Laser Radiation: Electron Transfer versus Proton Transfer. J Phys Chem Lett 2023; 14:4372-4380. [PMID: 37140167 DOI: 10.1021/acs.jpclett.2c03764] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Ultrafast H2+ and H3+ formation from ethanol is studied using pump-probe spectroscopy with an extreme ultraviolet (XUV) free-electron laser. The first pulse creates a dication, triggering H2 roaming that leads to H2+ and H3+ formation, which is disruptively probed by a second pulse. At photon energies of 28 and 32 eV, the ratio of H2+ to H3+ increases with time delay, while it is flat at a photon energy of 70 eV. The delay-dependent effect is ascribed to a competition between electron and proton transfer. High-level quantum chemistry calculations show a flat potential energy surface for H2 formation, indicating that the intermediate state may have a long lifetime. The ab initio molecular dynamics simulation confirms that, in addition to the direct emission, a small portion of H2 undergoes a roaming mechanism that leads to two competing pathways: electron transfer from H2 to C2H4O2+ and proton transfer from C2H4O2+ to H2.
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11
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He Y, Liu Z, Ott C, Pfeiffer AN, Sun S, Gaarde MB, Pfeifer T, Hu B. Resonant Perfect Absorption Yielded by Zero-Area Pulses. PHYSICAL REVIEW LETTERS 2022; 129:273201. [PMID: 36638297 DOI: 10.1103/physrevlett.129.273201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/11/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
We propose and study the manipulation of the macroscopic transient absorption of an ensemble of open two-level systems via temporal engineering. The key idea is to impose an ultrashort temporal gate on the polarization decay of the system by transient absorption spectroscopy, thus confining its free evolution and the natural reshaping of the excitation pulse. The numerical and analytical results demonstrate that even at moderate optical depths, the resonant absorption of light can be reduced or significantly enhanced by more than 5 orders of magnitude relative to that without laser manipulation. The achievement of the quasicomplete extinction of light at the resonant frequency, here referred to as resonant perfect absorption, arises from the full destructive interference between the excitation pulse and its subpulses developed and tailored during propagation, and is revealed to be connected with the formation of zero-area pulses in the time domain.
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12
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Kühn S, Cheung C, Oreshkina NS, Steinbrügge R, Togawa M, Bernitt S, Berger L, Buck J, Hoesch M, Seltmann J, Trinter F, Keitel CH, Kozlov MG, Porsev SG, Gu MF, Porter FS, Pfeifer T, Leutenegger MA, Harman Z, Safronova MS, López-Urrutia JRC, Shah C. New Measurement Resolves Key Astrophysical Fe XVII Oscillator Strength Problem. PHYSICAL REVIEW LETTERS 2022; 129:245001. [PMID: 36563261 DOI: 10.1103/physrevlett.129.245001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 07/27/2022] [Accepted: 08/23/2022] [Indexed: 06/17/2023]
Abstract
One of the most enduring and intensively studied problems of x-ray astronomy is the disagreement of state-of-the art theory and observations for the intensity ratio of two Fe XVII transitions of crucial value for plasma diagnostics, dubbed 3C and 3D. We unravel this conundrum at the PETRA III synchrotron facility by increasing the resolving power 2.5 times and the signal-to-noise ratio thousandfold compared with our previous work. The Lorentzian wings had hitherto been indistinguishable from the background and were thus not modeled, resulting in a biased line-strength estimation. The present experimental oscillator-strength ratio R_{exp}=f_{3C}/f_{3D}=3.51(2)_{stat}(7)_{sys} agrees with our state-of-the-art calculation of R_{th}=3.55(2), as well as with some previous theoretical predictions. To further rule out any uncertainties associated with the measured ratio, we also determined the individual natural linewidths and oscillator strengths of 3C and 3D transitions, which also agree well with the theory. This finally resolves the decades-old mystery of Fe XVII oscillator strengths.
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Mandal A, Rost JM, Pfeifer T, Singh KP. Widely tunable XUV harmonics using double IR pulses. OPTICS EXPRESS 2022; 30:45020-45030. [PMID: 36522913 DOI: 10.1364/oe.472385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/10/2022] [Indexed: 06/17/2023]
Abstract
Tunable attosecond pulses are necessary for various attosecond resolved spectroscopic applications, which can potentially be obtained through the tuning of high harmonic generation. Here we show theoretically, using the time-dependent Schrödinger equation and strong field approximation, a continuously tunable spectral shift of high-order harmonics by exploiting the interaction of two delayed identical infrared (IR) pulses within the single-atom response. The tuning spans more than twice the driving frequency (∼2ω) range, for several near-cutoff harmonics, with respect to only one control parameter: the change in delay between the two IR pulses. We show that two distinct mechanisms contribute to the spectral shift of the harmonic spectra. The dominant part of the spectral shift of the harmonics is due to the modulation of the central frequency of the composite IR-IR pulse with respect to delay. The second contribution comes from the non-adiabatic phase-shift of the recolliding electron wavepacket due to the change in amplitude of the subcycle electric field within the double pulse envelope. For optical few-cycle pulses this scheme can produce tunable attosecond pulse trains (APT), and in the single-cycle regime the same can be used for tuning isolated attosecond pulses (IAP). We quantify the dependence of tuning range and tuning rate on the laser pulse duration. We envision that the proposed scheme can be easily implemented with compact in-line setups for generating frequency tunable APT/IAP.
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14
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Oelmann JH, Heldt T, Guth L, Nauta J, Lackmann N, Wössner V, Kokh S, Pfeifer T, López-Urrutia JRC. Photoelectron tomography with an intra-cavity velocity-map imaging spectrometer at 100 MHz repetition rate. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:123303. [PMID: 36586896 DOI: 10.1063/5.0104679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
We present a compact velocity-map imaging (VMI) spectrometer for photoelectron imaging at 100 MHz repetition rate. Ultrashort pulses from a near-infrared frequency comb laser are amplified in a polarization-insensitive passive femtosecond enhancement cavity. In the focus, multi-photon ionization (MPI) of gas-phase atoms is studied tomographically by rotating the laser polarization. We demonstrate the functioning of the VMI spectrometer by reconstructing photoelectron angular momentum distributions from xenon MPI. Our intra-cavity VMI setup collects electron energy spectra at high rates, with the advantage of transferring the coherence of the cavity-stabilized femtosecond pulses to the electrons. In addition, the setup will allow studies of strong-field effects in nanometric tips.
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15
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Straub M, Ding T, Rebholz M, Borisova GD, Magunia A, Lindenblatt H, Meister S, Trost F, Wang Y, Palutke S, Braune M, Düsterer S, Treusch R, Greene CH, Moshammer R, Pfeifer T, Ott C. Differential Measurement of Electron Ejection after Two-Photon Two-Electron Excitation of Helium. PHYSICAL REVIEW LETTERS 2022; 129:183204. [PMID: 36374686 DOI: 10.1103/physrevlett.129.183204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
We report the measurement of the photoelectron angular distribution of two-photon single-ionization near the 2p^{2} ^{1}D^{e} double-excitation resonance in helium, benchmarking the fundamental nonlinear interaction of two photons with two correlated electrons. This observation is enabled by the unique combination of intense extreme ultraviolet pulses, delivered at the high-repetition-rate free-electron laser in Hamburg (FLASH), ionizing a jet of cryogenically cooled helium atoms in a reaction microscope. The spectral structure of the intense self-amplified spontaneous emission free-electron laser pulses has been resolved on a single-shot level to allow for post selection of pulses, leading to an enhanced spectral resolution, and introducing a new experimental method. The measured angular distribution is directly compared to state-of-the-art theory based on multichannel quantum defect theory and the streamlined R-matrix method. These results and experimental methodology open a promising route for exploring fundamental interactions of few photons with few electrons in general.
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Heeg KP, Bocklage L, Strohm C, Ott C, Lentrodt D, Haber J, Wille HC, Rüffer R, Gollwitzer J, Adolff CF, Schlage K, Sergeev I, Leupold O, Meier G, Keitel CH, Röhlsberger R, Pfeifer T, Evers J. Reply to: On yoctosecond science. Nature 2022; 608:E18-E19. [PMID: 35948703 DOI: 10.1038/s41586-022-04871-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Dahiya S, Tyagi A, Mandal A, Pfeifer T, Singh KP. Ultrathin picoscale white light interferometer. Sci Rep 2022; 12:8656. [PMID: 35606485 PMCID: PMC9126962 DOI: 10.1038/s41598-022-12620-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 04/27/2022] [Indexed: 11/09/2022] Open
Abstract
White light interferometry is a well established technique with diverse precision applications, however, the conventional interferometers such as Michelson, Mach-Zehnder or Linnik are large in size, demand tedious alignment for obtaining white light fringes, require noise-isolation techniques to achieve sub-nanometric stability and importantly, exhibit unbalanced dispersion causing uncertainty in absolute zero delay reference. Here, we demonstrate an ultrathin white light interferometer enabling picometer resolution by exploiting the wavefront division of a broadband incoherent light beam after transmission through a pair of micrometer thin identical glass plates. Spatial overlap between the two diffracted split wavefronts readily produce high-contrast and stable white light fringes, with unambiguous reference to absolute zero path-delay position. The colored fringes evolve when one of the ultrathin plates is rotated to tune the interferometer with picometric resolution over tens of μm range. Our theoretical analysis validates formation of fringes and highlights self-calibration of the interferometer for picoscale measurements. We demonstrate measurement of coherence length of several broadband incoherent sources as small as a few micrometer with picoscale resolution. Furthermore, we propose a versatile double-pass configuration using the ultrathin interferometer enabling a sample cavity for additional applications in probing dynamical properties of matter.
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Rupprecht P, Aufleger L, Heinze S, Magunia A, Ding T, Rebholz M, Amberg S, Mollov N, Henrich F, Haverkort MW, Ott C, Pfeifer T. Laser Control of Electronic Exchange Interaction within a Molecule. PHYSICAL REVIEW LETTERS 2022; 128:153001. [PMID: 35499899 DOI: 10.1103/physrevlett.128.153001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/01/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Electronic interactions play a fundamental role in atoms, molecular structure and reactivity. We introduce a general concept to control the effective electronic exchange interaction with intense laser fields via coupling to excited states. As an experimental proof of principle, we study the SF_{6} molecule using a combination of soft x-ray and infrared (IR) laser pulses. Increasing the IR intensity increases the effective exchange energy of the core hole with the excited electron by 50%, as observed by a characteristic spin-orbit branching ratio change. This work demonstrates altering electronic interactions by targeting many-particle quantum properties.
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19
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Srinivas H, Shobeiry F, Bharti D, Pfeifer T, Moshammer R, Harth A. High-repetition rate attosecond beamline for multi-particle coincidence experiments. OPTICS EXPRESS 2022; 30:13630-13646. [PMID: 35472972 DOI: 10.1364/oe.454553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
In this paper, a 3-dimensional photoelectron/ion momentum spectrometer (reaction microscope) combined with a table-top attosecond beamline based on a high-repetition rate (49 kHz) laser source is presented. The beamline is designed to achieve a temporal stability below 50 attoseconds. Results from measurements on systems like molecular hydrogen and argon dimers demonstrate the capabilities of this setup in observing the attosecond dynamics in 3D while covering the full solid angle for ionization processes having low cross-sections.
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Stierhof J, Kühn S, Winter M, Micke P, Steinbrügge R, Shah C, Hell N, Bissinger M, Hirsch M, Ballhausen R, Lang M, Gräfe C, Wipf S, Cumbee R, Betancourt-Martinez GL, Park S, Niskanen J, Chung M, Porter FS, Stöhlker T, Pfeifer T, Brown GV, Bernitt S, Hansmann P, Wilms J, Crespo López-Urrutia JR, Leutenegger MA. A new benchmark of soft X-ray transition energies of Ne , CO 2 , and SF 6 : paving a pathway towards ppm accuracy. THE EUROPEAN PHYSICAL JOURNAL. D, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 2022; 76:38. [PMID: 35273463 PMCID: PMC8888507 DOI: 10.1140/epjd/s10053-022-00355-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
ABSTRACT A key requirement for the correct interpretation of high-resolution X-ray spectra is that transition energies are known with high accuracy and precision. We investigate the K-shell features of Ne , CO 2 , and SF 6 gases, by measuring their photo ion-yield spectra at the BESSY II synchrotron facility simultaneously with the 1s-np fluorescence emission of He-like ions produced in the Polar-X EBIT. Accurate ab initio calculations of transitions in these ions provide the basis of the calibration. While the CO 2 result agrees well with previous measurements, the SF 6 spectrum appears shifted by ∼ 0.5 eV, about twice the uncertainty of the earlier results. Our result for Ne shows a large departure from earlier results, but may suffer from larger systematic effects than our other measurements. The molecular spectra agree well with our results of time-dependent density functional theory. We find that the statistical uncertainty allows calibrations in the desired range of 1-10 meV, however, systematic contributions still limit the uncertainty to ∼ 40-100 meV, mainly due to the temporal stability of the monochromator energy scale. Combining our absolute calibration technique with a relative energy calibration technique such as photoelectron energy spectroscopy will be necessary to realize its full potential of achieving uncertainties as low as 1-10 meV.
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Rebholz M, Ding T, Aufleger L, Hartmann M, Meyer K, Stooß V, Magunia A, Wachs D, Birk P, Mi Y, Borisova GD, da Costa Castanheira C, Rupprecht P, Magrakvelidze M, Thumm U, Roling S, Butz M, Zacharias H, Düsterer S, Treusch R, Brenner G, Ott C, Pfeifer T. XUV-Initiated Dissociation Dynamics of Molecular Oxygen (O 2). J Phys Chem A 2021; 125:10138-10143. [PMID: 34788037 PMCID: PMC8647076 DOI: 10.1021/acs.jpca.1c06033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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We
performed a time-resolved spectroscopy experiment on the dissociation
of oxygen molecules after the interaction with intense extreme-ultraviolet
(XUV) light from the free-electron laser in Hamburg at Deutsches Elektronen-Synchrotron.
Using an XUV-pump/XUV-probe transient-absorption geometry with a split-and-delay
unit, we observe the onset of electronic transitions in the O2+ cation near 50 eV photon energy, marking the end of
the progression from a molecule to two isolated atoms. We observe
two different time scales of 290 ± 53 and 180 ± 76 fs
for the emergence of different ionic transitions, indicating different
dissociation pathways taken by the departing oxygen atoms. With regard
to the emerging opportunities of tuning the central frequencies of
pump and probe pulses and of increasing the probe–pulse bandwidth,
future pump–probe transient-absorption experiments are expected
to provide a detailed view of the coupled nuclear and electronic dynamics
during molecular dissociation.
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Schotsch F, Zebergs I, Augustin S, Lindenblatt H, Hoibl L, Djendjur D, Schroeter CD, Pfeifer T, Moshammer R. TrapREMI: A reaction microscope inside an electrostatic ion beam trap. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:123201. [PMID: 34972421 DOI: 10.1063/5.0065454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/04/2021] [Indexed: 06/14/2023]
Abstract
A new experimental setup has been developed to investigate the reactions of molecular ions and charged clusters with a variety of projectile beams. An Electrostatic Ion Beam Trap (EIBT) stores fast ions at keV energies in an oscillatory motion. By crossing it with a projectile beam, e.g., an IR laser, molecular reactions can be induced. We implemented a Reaction Microscope (REMI) in the field-free region of the EIBT to perform coincidence spectroscopy on the resulting reaction products. In contrast to prior experiments, this unique combination of techniques allows us to measure the 3D momentum-vectors of ions, electrons, and neutrals as reaction products in coincidence. At the same time, the EIBT allows for advanced target preparation techniques, e.g., relaxation of hot molecules during storage times of up to seconds, autoresonance cooling, and recycling of target species, which are difficult to prepare. Otherwise, the TrapREMI setup can be connected to a variety of projectile sources, e.g., atomic gas jets, large-scale radiation facilities, and ultrashort laser pulses, which enable even time-resolved studies. Here, we describe the setup and a first photodissociation experiment on H2 +, which demonstrates the ion-neutral coincidence detection in the TrapREMI.
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Kurz N, Fischer D, Pfeifer T, Dorn A. Reaction microscope for investigating ionization dynamics of weakly bound alkali dimers. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:123202. [PMID: 34972432 DOI: 10.1063/5.0069506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/12/2021] [Indexed: 06/14/2023]
Abstract
We report on the implementation of a far-off-resonant, optical dipole force trap in a reaction microscope combined with a magneto-optical trap. Kinematically complete multi-photon ionization experiments were performed on optically trapped 6Li atoms and photo-associated 6Li2 molecules in their highest vibrational state. The apparatus allows us to distinguish different ionization mechanisms related to the presence of the IR field of the optical dipole trap that can occur during ionization of 6Li and 6Li2 in strong fields. In a series of proof-of-principle experiments, we detect weakly bound dimers via three-photon ionization with femtosecond pulses (τ = 30 fs) at a central wavelength of 780 nm and measure directly the momenta of the photoelectrons in coincidence with recoil ions.
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Stark J, Warnecke C, Bogen S, Chen S, Dijck EA, Kühn S, Rosner MK, Graf A, Nauta J, Oelmann JH, Schmöger L, Schwarz M, Liebert D, Spieß LJ, King SA, Leopold T, Micke P, Schmidt PO, Pfeifer T, Crespo López-Urrutia JR. An ultralow-noise superconducting radio-frequency ion trap for frequency metrology with highly charged ions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:083203. [PMID: 34470420 DOI: 10.1063/5.0046569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
We present a novel ultrastable superconducting radio-frequency (RF) ion trap realized as a combination of an RF cavity and a linear Paul trap. Its RF quadrupole mode at 34.52 MHz reaches a quality factor of Q ≈ 2.3 × 105 at a temperature of 4.1 K and is used to radially confine ions in an ultralow-noise pseudopotential. This concept is expected to strongly suppress motional heating rates and related frequency shifts that limit the ultimate accuracy achieved in advanced ion traps for frequency metrology. Running with its low-vibration cryogenic cooling system, electron-beam ion trap, and deceleration beamline supplying highly charged ions (HCIs), the superconducting trap offers ideal conditions for optical frequency metrology with ionic species. We report its proof-of-principle operation as a quadrupole-mass filter with HCIs and trapping of Doppler-cooled 9Be+ Coulomb crystals.
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Belsa B, Amini K, Liu X, Sanchez A, Steinle T, Steinmetzer J, Le AT, Moshammer R, Pfeifer T, Ullrich J, Moszynski R, Lin CD, Gräfe S, Biegert J. Erratum: Publisher's Note: "Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia" [Struct. Dyn. 8, 014301 (2021)]. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2021; 8:049901. [PMID: 34497865 PMCID: PMC8410134 DOI: 10.1063/4.0000117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Indexed: 06/13/2023]
Abstract
[This corrects the article DOI: 10.1063/4.0000046.].
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