Article
Optics
Rocio Borrego-Varillas, Matteo Lucchini
Summary: This study investigates the effects of Fano resonances in attosecond streaking spectrograms and the application of standard phase-reconstruction algorithms. It shows that despite the hindrance of infrared coupling, standard algorithms can still retrieve photoemission delays under certain conditions. Additionally, two strategies are proposed to study the strength of IR coupling using the attosecond streaking technique.
Article
Optics
Miao Yu, Kun Liu, Min Li, Jiaqing Yan, Chuanpeng Cao, Jia Tan, Jintai Liang, Keyu Guo, Wei Cao, Pengfei Lan, Qingbin Zhang, Yueming Zhou, Peixiang Lu
Summary: This study proposes and demonstrates a new scheme for accurately determining the tunneling time of an electron. By using a weak laser field to streak the tunneling current produced by a strong laser field, the tunneling ionization time can be retrieved with high precision. This approach overcomes previous difficulties in attoclock measurements and provides a direct method for attosecond time-resolved imaging of electron motion.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Optics
Peng Xu, Xianglin Wang, Huabao Cao, Hao Yuan, Liang-Wen Pi, Yishan Wang, Yuxi Fu, Yonglin Bai, Wei Zhao
Summary: In this study, a theoretical non-collinear attosecond streaking scheme is proposed, which enables real-time measurement and even the potential for single-shot measurement of attosecond pulses without a time delay scan. By projecting time-delay information into longitudinal space, both horizontally and vertically, attosecond pulse characterization with temporal-spatial coupling is achieved. Our calculations demonstrate the accurate characterization of pulses as short as 70 as with pulse front and wavefront tilt. This study not only provides a method for real-time attosecond pulse measurement, but also an approach for attosecond pump-probe experiments without time delay scan.
Article
Optics
Xi Zhao, Siqi Li, Taran Driver, Van-Hung Hoang, Anh-Thu Le, James P. Cryan, Agostino Marinelli, C. D. Lin
Summary: Most traditional attosecond pulse retrieval algorithms cannot be used for attosecond pulses generated from free-electron x-ray lasers. However, using a circularly polarized infrared laser, a modified retrieval algorithm has been successfully applied to characterize single-shot attosecond pulses in recent experiments.
Article
Physics, Multidisciplinary
Xi Zhao, Jiahao Liu, Guoxiang Luo, Changli Wei
Summary: The study of photoionization time delays has been controversial due to discrepancies between experimental measurements and theoretical simulations. The development of a new time delay retrieval method has provided a more accurate approach, highlighting the importance of characterizing the entire bandwidth of the wave packet in photoionization processes.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Feng Wang, Qing Liao, Kai Liu, Meiyan Qin, Xiaofan Zhang, Qingbin Zhang, Wei Cao, Liang-Wen Pi, Yueming Zhou, Peixiang Lu
Summary: Attosecond metrology allows direct measurement of the attosecond emission time of photoexcited electrons from matter, providing unprecedented insights into electron transition processes. By using attosecond photoemission delays to image picometer-resolved emission positions, the electronic dynamics in laser-assisted single-photon ionization processes can be accurately captured. This imaging technique traces the emission position to the average position of spatially coherent superposition of electron waves upon photoexcitation, predicting emission positions that coincide with the orbital radius of hydrogen-like atoms' ground state.
Article
Physics, Multidisciplinary
G. Hajivassiliou, M. Kassapis, J. W. G. Tisch
Summary: Attosecond streaking is a powerful technique for characterising femtosecond to attosecond optical pulses. The use of machine learning improves processing speed and noise resilience for retrieving data from streaking measurements. The implementation of a convolutional neural network significantly reduces training and retrieval times, enabling near kHz retrieval rates.
NEW JOURNAL OF PHYSICS
(2023)
Article
Multidisciplinary Sciences
Jasper Peschel, David Busto, Marius Plach, Mattias Bertolino, Maria Hoflund, Sylvain Maclot, Jimmy Vinbladh, Hampus Wikmark, Felipe Zapata, Eva Lindroth, Mathieu Gisselbrecht, Jan Marcus Dahlstroem, Anne L'Huillier, Per Eng-Johnsson
Summary: Understanding the ultrafast dynamics of photoionization requires characterizing all underlying ionization channels. In this study, the authors use an interferometry technique based on attosecond pulses to measure the phase and amplitude of individual angular momentum channels in the photoionization of neon.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Kan Wang, Yong Fu, Baochang Li, Xiangyu Tang, Bincheng Wang, Zhong Guan, C. D. Lin, Cheng Jin
Summary: In this study, we propose a method to retrieve an isolated attosecond pulse (IAP) in the time domain through the modulation of high-harmonic generation (HHG) spectra, using a time-delayed intense few-cycle infrared or mid-infrared laser. The retrieval algorithm is derived based on the strong-field approximation and a quantitative rescattering model. We demonstrate that both narrowband extreme ultraviolet (XUV) pulses and broadband soft x-ray (SXR) pulses can be characterized accurately using the HHG streaking spectra.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Aderonke S. Folorunso, Adam Bruner, Francois Mauger, Kyle A. Hamer, Samuel Hernandez, Robert R. Jones, Louis F. DiMauro, Mette B. Gaarde, Kenneth J. Schafer, Kenneth Lopata
Summary: First-principles calculations were used to investigate the modes of attosecond charge migration in halogenated hydrocarbon chains. Low-frequency charge migration modes were found to propagate across the molecule, with a speed largely independent of molecule length but dependent on halogen mass. Increasing halogen mass led to the charge behaving more like a particle as it moved across the molecule.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Gabriel A. Stewart, Paul Hoerner, Duke A. Debrah, Suk Kyoung Lee, H. Bernhard Schlegel, Wen Li
Summary: A phase-resolved two-electron-angular-streaking method is developed to investigate the spatial evolution of an ultrafast spin-orbit wave packet in the krypton cation and the motion of a faster wave packet in the xenon cation. The refilling of an electronic hole is observed 1.2 fs after its production, and the filling occurs on the opposite side of the hole's birth.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Vladislav V. Serov, Anatoli S. Kheifets
Summary: In this study, the orientation and two-center interference effects in attosecond time-resolved photoionization of the H-2 molecule are investigated. The time resolution of extreme-ultraviolet ionization of H-2 is achieved by utilizing the phase retrieval capability of attosecond angular streaking previously demonstrated by Kheifets et al (2022 Phys. Rev. A 106 033106). When applied to H-2, this technique provides an anisotropic phase and time delay that depend sensitively on the molecular axis orientation. The photoelectron momentum distribution exhibits a distinct two-center interference pattern. When the interference formula of Walter and Briggs (1999 J. Phys. B 32 2487) is applied, the effective photoelectron momentum appears to be greater than the asymptotic momentum at the detector, which is explained by the presence of a molecular potential well surrounding the photoemission center.
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS
(2023)
Article
Multidisciplinary Sciences
Dominik Ertel, David Busto, Ioannis Makos, Marvin Schmoll, Jakub Benda, Hamed Ahmadi, Matteo Moioli, Fabio Frassetto, Luca Poletto, Claus Dieter Schroeter, Thomas Pfeifer, Robert Moshammer, Zdenek Masin, Serguei Patchkovskii, Giuseppe Sansone
Summary: In extreme ultraviolet spectroscopy, the process of photoionization in a molecule due to absorption of a single photon can trigger rapid nuclear motion in the cation. By using attosecond photoelectron interferometry to measure two-color photoionization spectra, the influence of nuclear dynamics on electronic wave packet coherence properties can be studied. Our experiments with a mixture of methane and deuteromethane reveal that different nuclear evolution in isotopologues can modify the oscillations of photoelectron peaks.
Article
Physics, Multidisciplinary
Xiaofan Zhang, Xiaomeng Ma
Summary: We theoretically investigate the photoelectron momentum distributions of 1s and 2p(x, y) states of hydrogen by twisted attosecond X waves carrying orbital angular momentum based on first-order perturbation theory. The photoionization spectra as a function of photoelectron energy and emission angle are analyzed respectively. The results indicate that there are interference fringes in the energy spectra and more nodes in the angular distributions. These angular nodes are attributed to both orbital structure and the temporal-spatial structure of X waves. We derive an equation that can quantitatively describe the angular nodes in the photoelectron angular distributions. Our results and analyses indicate that the angular distribution is an important observation for the investigation of the information of both orbitals and X waves.
FRONTIERS IN PHYSICS
(2023)
Article
Optics
J. I. A. X. I. N. Han, X. I. A. N. G. Y. U. Tang, Z. H. I. M. I. N. G. Yin, K. A. N. Wang, Y. O. N. G. Fu, B. E. I. Y. U. Wang, Y. A. N. B. O. Chen, C. H. Zhang, C. H. E. N. G. Jin
Summary: This study reveals that fractional high harmonics (FHHs) generated by a short duration Laguer re-Gaussian laser beam are responsible for the change in helical attosecond pulse train (APT) with azimuthal angle. These harmonics possess gap and minimum structures in the annular intensity profile and exhibit discontinuous phase distribution along the azimuthal angle. By combining selected OAM modes, the features of FHHs can be identified. Furthermore, the generation of FHHs and the dependence of helical APTs on azimuthal angle can be altered by varying the macroscopic condition.
Article
Optics
Alexander Nussbaum-Lapping, Christopher R. Phillips, Benjamin Willenberg, Justinas Pupeikis, Ursula Keller
Summary: This study demonstrates the complete characterization of SESAMs using an equivalent time sampling apparatus, allowing for fast and reliable determination of the devices' nonlinear properties. The measurements show good agreement with conventional methods, revealing slower recovery at higher fluence values and the impact of polarization dependence.
APPLIED PHYSICS B-LASERS AND OPTICS
(2022)
Article
Optics
O. Chuluunbaatar, S. Houamer, Yu Popov, I. P. Volobuev, M. Kircher, R. Doerner
Summary: Recent experiments on single and double ionization of atoms by Compton scattering have shown the potential for establishing new methods of dynamical spectroscopy, specifically for studying electron-electron correlations. In this paper, the possibility of using double ionization of the helium atom by Compton scattering as a tool for direct spectroscopy of electron-electron correlations is explored. The authors propose a computationally efficient non-relativistic theoretical description of the process using the Kramers-Heisenberg-Waller approximation.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2022)
Article
Physics, Multidisciplinary
Rebecca Boll, Julia M. Schaefer, Benoit Richard, Kilian Fehre, Gregor Kastirke, Zoltan Jurek, Markus S. Schoeffler, Malik M. Abdullah, Nils Anders, Thomas M. Baumann, Sebastian Eckart, Benjamin Erk, Alberto De Fanis, Reinhard Doerner, Sven Grundmann, Patrik Grychtol, Alexander Hartung, Max Hofmann, Markus Ilchen, Ludger Inhester, Christian Janke, Rui Jin, Max Kircher, Katharina Kubicek, Maksim Kunitski, Xiang Li, Tommaso Mazza, Severin Meister, Niklas Melzer, Jacobo Montano, Valerija Music, Giammarco Nalin, Yevheniy Ovcharenko, Christopher Passow, Andreas Pier, Nils Rennhack, Jonas Rist, Daniel E. Rivas, Daniel Rolles, Ilme Schlichting, Lothar Ph H. Schmidt, Philipp Schmidt, Juliane Siebert, Nico Strenger, Daniel Trabert, Florian Trinter, Isabel Vela-Perez, Rene Wagner, Peter Walter, Miriam Weller, Pawel Ziolkowski, Sang-Kil Son, Artem Rudenko, Michael Meyer, Robin Santra, Till Jahnke
Summary: Intense femtosecond X-ray pulses can visualize the structural dynamics of exploding photoionized molecules, providing important insights into chemical reactions.
Article
Optics
S. L. Camenzind, D. Koenen, B. Willenberg, J. Pupeikis, C. R. Phillips, U. Keller
Summary: Pulse trains emitted from dual-comb systems with low relative timing jitter can be measured using an optical heterodyne detection approach. A new laser with precise timing and low noise has been characterized using this technique.
Article
Optics
Ajanta Barh, B. Ozgur Alaydin, Jonas Heidrich, Marco Gaulke, Matthias Golling, Christopher R. Phillips, Ursula Keller
Summary: Femtosecond lasers with high repetition rates are attractive for spectroscopic applications. However, current laser sources at long wavelengths face limitations in output power and repetition rates. This study presents a high-power ultrafast laser oscillator operating at multi-GHz repetition rates using a specific laser modelocked with an SESAM. The results open up possibilities for efficient spectroscopy above 2 μm.
Article
Physics, Multidisciplinary
Laura Cattaneo, Luca Pedrelli, Roger Y. Bello, Alicia Palacios, Phillip D. Keathley, Fernando Martin, Ursula Keller
Summary: This letter investigates the impact of nuclear motion on the measurement of electronic dynamics using two popular attosecond techniques. The results show that streaking is a better choice for isolating attosecond electron dynamics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Kang Lin, Simon Brennecke, Hongcheng Ni, Xiang Chen, Alexander Hartung, Daniel Trabert, Kilian Fehre, Jonas Rist, Xiao-Min Tong, Joachim Burgdoerfer, Lothar Ph H. Schmidt, Markus S. Schoeffler, Till Jahnke, Maksim Kunitski, Feng He, Manfred Lein, Sebastian Eckart, Reinhard Doerner
Summary: We experimentally and theoretically investigate the influence of the magnetic component of an electromagnetic field on high-order above-threshold ionization of xenon atoms driven by ultrashort femtosecond laser pulses. The nondipole shift of the electron momentum distribution along the light propagation direction for high energy electrons beyond the 2Up classical cutoff is found to be vastly different from that below this cutoff. Large-angle rescattering of the electrons strongly alters the partitioning of the photon momentum between electron and ion. Our work paves the way toward understanding the physics of extreme light-matter interactions at long wavelengths and high electron kinetic energies.
PHYSICAL REVIEW LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Jonas Heidrich, Marco Gaulke, Matthias Golling, Behcet Ozgur Alaydin, Ajanta Barh, Ursula Keller
Summary: This study presents the first modelocked backside-cooled GaSb VECSEL operating above 2 μm. By using a two quantum well InGaSb SESAM in a V-shaped cavity arrangement, femtosecond and picosecond mode-locking were achieved, and the performance and intracavity group delay dispersion of the laser were investigated.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Lianrong Zhou, Hongcheng Ni, Zhejun Jiang, Junjie Qiang, Wenyu Jiang, Wenbin Zhang, Peifen Lu, Jin Wen, Kang Lin, Meifang Zhu, Reinhard Doerner, Jian Wu
Summary: The formation of trihydrogen cation driven by light has been of great interest due to its important role in initiating chemical reactions in interstellar clouds. Previous studies focused on the formation of H-3(+) or D-3(+) from unimolecular reactions, but we observed and characterized the ultrafast formation of D-3(+) from a bimolecular reaction. Molecular dynamics simulations provided an intuitive representation of the reaction dynamics, which matched well with experimental observations. Additionally, we demonstrated control over the emission direction of D-3(+) using a tailored two-colour femtosecond laser field, based on the mechanism known for light control of electron localization in single molecules.
Article
Physics, Multidisciplinary
D. Trabert, N. Anders, A. Geyer, M. Hofmann, M. S. Schoeffler, L. Ph. H. Schmidt, T. Jahnke, M. Kunitski, R. Doerner, S. Eckart
Summary: We experimentally studied the strong-field ionization of the argon dimer in a co-rotating two-color laser field. A subcycle interference pattern in the photoelectron momentum distribution was observed, and the Wigner time delay was inferred using holographic angular streaking of electrons. It was found that the Wigner time delay varied by more than 400 attoseconds with respect to the electron emission direction relative to the molecular axis. The measured time delay was independent of the parity of the dimercation and agreed well with the theoretical model based on the ionization of an aligned atomic p orbital.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
G. Nalin, N. M. Novikovskiy, K. Fehre, N. Anders, D. Trabert, S. Grundmann, M. Kircher, A. Khan, R. Tomar, M. Hofmann, M. Waitz, I. Vela-Perez, G. Kastirke, J. Siebert, D. Tsitsonis, C. Kuestner-Wetekam, L. Marder, J. Viehmann, F. Trinter, H. Fukuzawa, K. Ueda, J. B. Williams, A. Knie, R. Doerner, M. S. Schoeffler, T. Jahnke, Ph. V. Demekhin
Summary: We experimentally and theoretically studied the differential photoelectron circular dichroism (PECD) of O 1s photoelectrons of R-trifluoromethyloxirane enantiomers with different photoelectron kinetic energies. By using cold target recoil ion momentum spectroscopy, we detected the photoelectrons and two ionic molecular fragments simultaneously, enabling determination of the molecule's orientation in the laboratory frame and obtaining molecular-frame photo-electron diffraction patterns for deducing the differential PECD. The observed normalized PECD strength clearly exceeds 50% for given molecular orientations and photoelectron emission directions, consistent with relaxed-core Hartree-Fock calculations using the single center method. These results support our recent discovery of a significant differential PECD in O 1s photoemission of the methyloxirane molecule.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
Andreas Hans, Florian Trinter, Philipp Schmidt, Sebastian Eckart, Sven Grundmann, Gregor Hartmann, Xaver Holzapfel, Carolin Honisch, Gregor Kastirke, Max Kircher, Niklas Melzer, Christian Ozga, Clemens Richter, Jonas Rist, Markus Schoeffler, Daniel Trabert, Isabel Vela-Perez, Johannes H. Viehmann, Miriam Weller, Reinhard Doerner, Uwe Hergenhahn, Arno Ehresmann, Andre Knie, Kirill Gokhberg, Aryya Ghosh, Till Jahnke
Summary: The role of interatomic and intermolecular energy and charge-transfer processes in weakly bound matter is currently debated. Two mechanisms of single-photon two-site double ionization in Ne dimers and clusters are discussed, occurring competitively or subsequently to resonant interatomic Coulombic decay (rICD). The first mechanism is photoelectron-impact ionization, enhanced by resonant excitation. The second mechanism is collisional ionization of energetic Rydberg atoms produced by rICD in Ne clusters and ionized by collisions with neutrals.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Atomic, Molecular & Chemical
Sven Grundmann, Florian Trinter, Yong-Kang Fang, Kilian Fehre, Nico Strenger, Andreas Pier, Leon Kaiser, Max Kircher, Liang-You Peng, Till Jahnke, Reinhard Doerner, Markus S. Schoeffler
Summary: We experimentally investigated the quasifree mechanism (QFM) in one-photon double ionization of He and H-2, revealing the four-fold symmetry in the angular emission pattern of QFM electrons from H-2 double ionization and providing evidence that the photon momentum is not imparted onto the center of mass in quasifree photoionization.
Article
Chemistry, Physical
Kilian Fehre, Florian Trinter, Nikolay M. Novikovskiy, Sven Grundmann, Dimitrios Tsitsonis, Sebastian Eckart, Leonie Bauer, Maria Hilzinger, Till Jahnke, Reinhard Dorner, Philipp V. Demekhin, Markus S. Schoffler
Summary: This study presents a joint experimental and theoretical investigation of the differential photoelectron circular dichroism (PECD) in inner-shell photoionization of trifluoromethyloxirane. By adjusting the photon energy of the circularly polarized synchrotron radiation, the researchers examined the photoionization of different atoms and observed significant differences in the PECD signals.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
X. Li, A. Rudenko, M. S. Schoeffler, N. Anders, Th M. Baumann, S. Eckart, B. Erk, A. De Fanis, K. Fehre, R. Doerner, L. Foucar, S. Grundmann, P. Grychtol, A. Hartung, M. Hofmann, M. Ilchen, Ch Janke, G. Kastirke, M. Kircher, K. Kubicek, M. Kunitski, T. Mazza, S. Meister, N. Melzer, J. Montano, V Music, G. Nalin, Y. Ovcharenko, Ch Passow, A. Pier, N. Rennhack, J. Rist, D. E. Rivas, I Schlichting, L. Ph H. Schmidt, Ph Schmidt, J. Siebert, N. Strenger, D. Trabert, F. Trinter, I Vela-Perez, R. Wagner, P. Walter, M. Weller, P. Ziolkowski, A. Czasch, D. Rolles, M. Meyer, T. Jahnke, R. Boll
Summary: This study demonstrates that Coulomb-explosion imaging with ultrashort x-ray pulses is a promising technique for determining the three-dimensional geometry of polyatomic systems by measuring ion momenta.
PHYSICAL REVIEW RESEARCH
(2022)
