| 1. |
- Jahn, Olga, et al.
(författare)
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Towards intense isolated attosecond pulses from relativistic surface high harmonics
- 2019
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Ingår i: Optica. - : Optical Society of America. - 2334-2536. ; 6:3, s. 280-287
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Tidskriftsartikel (refereegranskat)abstract
- Relativistic surface high harmonics have been considered a unique source for the generation of intense isolated attosecond pulses in the extreme ultra-violet and x-ray spectral ranges. Their practical realization, however, is still a challenging task and requires identification of optimum experimental conditions and parameters. Here, we present measurements and particle-in-cell simulations to determine the optimum values for the most important parameters. In particular, we investigate the dependence of harmonics efficiency, divergence, and beam quality on the pre-plasma scale length as well as identify the optimum conditions for generation of isolated attosecond pulses by measuring the dependence of the harmonics spectrum on the carrier - envelope phase of the driving infrared field. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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| 2. |
- Leshchenko, Vyacheslav E., et al.
(författare)
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On-target temporal characterization of optical pulses at relativistic intensity
- 2019
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Ingår i: Light. - : Nature Publishing Group. - 2095-5545 .- 2047-7538. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- High-field experiments are very sensitive to the exact value of the peak intensity of an optical pulse due to the nonlinearity of the underlying processes. Therefore, precise knowledge of the pulse intensity, which is mainly limited by the accuracy of the temporal characterization, is a key prerequisite for the correct interpretation of experimental data. While the detection of energy and spatial profile is well established, the unambiguous temporal characterization of intense optical pulses, another important parameter required for intensity evaluation, remains a challenge, especially at relativistic intensities and a few-cycle pulse duration. Here, we report on the progress in the temporal characterization of intense laser pulses and present the relativistic surface second harmonic generation dispersion scan (RSSHG-D-scan)—a new approach allowing direct on-target temporal characterization of high-energy, few-cycle optical pulses at relativistic intensity.
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| 3. |
- Liu, Qingcao, et al.
(författare)
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Ionization-Induced Subcycle Metallization of Nanoparticles in Few-Cycle Pulses
- 2020
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 7:11, s. 3207-3215
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Tidskriftsartikel (refereegranskat)abstract
- Strong-field laser-matter interactions in nanoscale targets offer unique avenues for the generation and detailed characterization of matter under extreme conditions. Field-driven, subcycle ionization-induced metallization of nanoscale solids in intense laser fields has been predicted (Peltz et al. Time-Resolved X-ray Imaging of Anisotropic Nanoplasma Expansion. Phys. Rev. Lett. 2014, 113, 133401), but its observation was hampered by a lack of a smoking gun. Here, we report the ultrafast metallization of isolated dielectric and semiconducting nanoparticles under intense few-cycle laser pulses. The highest-energy electron emission is found to be a decisive proof that shows a characteristic cutoff modification to a metallic limit for intensities high enough to ignite carrier avalanching in the volume of the particles. Semiclassical Mean-field Mie Monte-Carlo transport simulations reveal the underlying dynamics and explain the observed evolution by near-field driven electron backscattering from the metallizing target.
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