We investigate MeV-level attosecond electron bunches from ultrashort-pulse laser-solid interactions through similarities between experimental and simulated electron energy spectra. We show measurements of the bunch duration and temporal structure from particle-in-cell simulations. The experimental observation of such bunches favors specular reflection direction when focusing the laser pulse onto a subwavelength boundary of thick overdense plasmas at grazing incidence. Particle-in-cell simulation further reveals that the attosecond duration is a result of ultra-thin ([Formula: see text]tenth of a micron) gaps of zero electromagnetic energy density in the modulated reflected radiation, while the bunching (locally peaked electron concentration) comes from the highly-directional electron angular distribution acquired by the electrons in a grazing incidence setup. To isolate a single electron bunch, we perform simulations using 1-cycle laser pulses and analyze the effect of carrier-envelop phase with particle tracking. The duration of the electron bunch can be further decreased by increasing the laser intensity and the focal spot size, while its direction can be changed by tuning the preplasma density gradient.
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http://dx.doi.org/10.1038/s41598-020-75418-6 | DOI Listing |
Phys Rev Lett
December 2024
Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China.
We have observed the laser-assisted dynamic interference in the electron spectra triggered by attosecond pulse trains. The fingerprints of finer interference fringes, much smaller than the laser photon energy, have been clearly identified experimentally. Our measurements are successfully reproduced by theoretical simulations utilizing the numerical solution to the time-dependent Schrödinger equation and the strong-field approximation.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China.
Phys Rev Lett
December 2024
Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel; Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel; and The Helen Diller Quantum Center, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Attosecond observations of coherent electron dynamics in molecules and nanostructures can be achieved by combining conventional scanning tunneling microscopy (STM) with ultrashort femtosecond laser pulses. While experimental studies in the subcycle regime are under way, a robust strong-field theory description has remained elusive. Here we devise a model based on the strong-field approximation.
View Article and Find Full Text PDFNature
December 2024
Institute of Physics, University of Freiburg, Freiburg, Germany.
Tailored light-matter interactions in the strong coupling regime enable the manipulation and control of quantum systems with up to unit efficiency, with applications ranging from quantum information to photochemistry. Although strong light-matter interactions are readily induced at the valence electron level using long-wavelength radiation, comparable phenomena have been only recently observed with short wavelengths, accessing highly excited multi-electron and inner-shell electron states. However, the quantum control of strong-field processes at short wavelengths has not been possible, so far, because of the lack of pulse-shaping technologies in the extreme ultraviolet (XUV) and X-ray domain.
View Article and Find Full Text PDFNat Commun
November 2024
Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
Attosecond science has demonstrated that electrons can be controlled on the sub-cycle time scale of an optical waveform, paving the way towards optical frequency electronics. However, these experiments historically relied on high-energy laser pulses and detection not suitable for microelectronic integration. For practical optical frequency electronics, a system suitable for integration and capable of generating detectable signals with low pulse energies is needed.
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