| 1. |
- Heissler, P., et al.
(författare)
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Multi‑μJ harmonic emission energy from laser‑driven plasma
- 2015
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Ingår i: Applied physics. B, Lasers and optics (Print). - : Springer. - 0946-2171 .- 1432-0649. ; 118:2, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- We report on simultaneous efficiency and divergence measurements for harmonics from solid targets generated by the relativistic oscillating mirror mechanism. For a value of the normalized vector potential of aL≃1.5aL≃1.5, we demonstrate the generation of 30 μJ high-harmonic radiation in a 17±317±3 mrad divergence cone. This corresponds to a conversion efficiency of ≳≳ 10−4 in the 17–80 nm range into a well-confined beam. Presuming phase-locked harmonics, our results predict unprecedented levels of average power for a single attosecond pulse in the generated pulse train. Results of PIC simulations raise the prospect of attaining efficiencies of a few percent at higher laser intensities.
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| 2. |
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| 3. |
- Kormin, Dmitrii, et al.
(författare)
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Spectral interferometry with waveform-dependent relativistic high-order harmonics from plasma surfaces
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of ultra-intense laser pulses with matter opened the way to generate the shortest light pulses available nowadays in the attosecond regime. Ionized solid surfaces, also called plasma mirrors, are promising tools to enhance the potential of attosecond sources in terms of photon energy, photon number and duration especially at relativistic laser intensities. Although the production of isolated attosecond pulses and the understanding of the underlying interactions represent a fundamental step towards the realization of such sources, these are challenging and have not yet been demonstrated. Here, we present laser-waveform-dependent high-order harmonic radiation in the extreme ultraviolet spectral range supporting well-isolated attosecond pulses, and utilize spectral interferometry to understand its relativistic generation mechanism. This unique interpretation of the measured spectra provides access to unrevealed temporal and spatial properties such as spectral phase difference between attosecond pulses and field-driven plasma surface motion during the process.
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| 4. |
- Ma, Guangjin, et al.
(författare)
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Intense circularly polarized attosecond pulse generation from relativistic laser plasmas using few-cycle laser pulses
- 2016
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Ingår i: Optics Express. - 1094-4087. ; 24:9, s. 10057-10065
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the polarization of attosecond light pulses generated from relativistic few-cycle laser pulse interaction with the surface of overdense plasmas using particle-in-cell simulation. Under suitable conditions, a desired polarization state of the generated attosecond pulse can be achieved by controlling the polarization of the incident laser. In particular, an elliptically polarized laser pulse of suitable ellipticity can generate an almost circularly polarized attosecond pulse without compromising the harmonic generation efficiency. The process is thus applicable as a new tabletop circularly-polarized XUV radiation source for probing attosecond phenomena with high temporal resolution.
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| 5. |
- Ma, Guangjin, et al.
(författare)
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Intense isolated attosecond pulse generation from relativistic laser plasmas using few-cycle laser pulses
- 2015
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Ingår i: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674. ; 22:3
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Tidskriftsartikel (refereegranskat)abstract
- We have performed a systematic study through particle-in-cell simulations to investigate the generation of attosecond pulse from relativistic laser plasmas when laser pulse duration approaches the few-cycle regime. A significant enhancement of attosecond pulse energy has been found to depend on laser pulse duration, carrier envelope phase, and plasma scale length. Based on the results obtained in this work, the potential of attaining isolated attosecond pulses with ∼100 μJ energy for photons >16 eV using state-of-the-art laser technology appears to be within reach.
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| 6. |
- Ma, Guangjin, et al.
(författare)
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Isolated attosecond light pulse generation from plasma surfaces at varying laser intensities and incidence angles
- 2022
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Ingår i: 1st International Conference on UltrafastX 2021. - : SPIE - International Society for Optical Engineering.
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Konferensbidrag (refereegranskat)abstract
- Harmonics from relativistic laser driven plasma surfaces is a prospective high energy attosecond light source infuture XUV pump-probe experiments. Among all the schemes, the most ecient and direct way to realize anisolated attosecond pulse is through using a few-cycle laser as the driving pulse. The two goodness criteria: thelaser to harmonics energy conversion eciency and the \purity" of an isolated attosecond pulse are generallydetermined by a combination of interaction parameters. Through using particle-in-cell simulations and relativisticelectron dynamics model analyses, we explain how these two criteria are a ected by the laser intensity, incidenceangle, carrier-envelope phase, and the plasma scale length. We found that, there exist an optimal plasma scalelength and an optimal incidence angle to eciently generate harmonics and intense attosecond light pulses.When other parameters are xed, using a moderately intense relativistic laser or using a large incidence anglecould result in a higher isolation degree as well as a broader range of controlling parameters to realize an isolatedattosecond light pulse.
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| 7. |
- Ma, Guangjin, et al.
(författare)
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Laser intensity and incidence angle dependent attosecond light pulse generation from relativistic laser plasma surfaces
- 2022
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Ingår i: Sixth international symposium on laser interaction with matter (LIMIS 2022). - : SPIE - International Society for Optical Engineering.
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Konferensbidrag (refereegranskat)abstract
- Relativistic high-order harmonics from a few-cycle laser driven plasma surface is a very promising source of anintense and isolated attosecond light pulse. The laser to harmonics conversion efficiency and the “purity” ofan isolated attosecond light pulse are generally determined by a combination of interaction parameters, suchas laser intensities, incidence angles, pulse durations, carrier-envelope phases and plasma scale lengths. Wehad already previously investigated the effect of a three-parameter combination of the laser pulse duration,the carrier-envelope phase and the plasma scale length. To complement our previous work, the parametricdependence of the other two three-parameter combinations: the carrier-envelope phase, the plasma scale length,either combined with the laser intensity or the incidence angle, were systematically investigated through onedimensional particle-in-cell simulations. We found that, although the impact of parameter combinations onattosecond pulse generations is generally complicated, there exist however an optimal plasma scale length and anoptimal incidence angle to efficiently generate high-order harmonics and intense attosecond light pulses. Whenother parameters are fixed, a moderately intense relativistic laser is more advantageous to realize an isolatedattosecond light pulse in a broad controlling parameters range. And a larger incidence angle favors a higherisolation degree as well as a broader range of controlling parameters towards the generation of intense isolatedattosecond light pulses. In order to interpret these simulation results, we have modeled the correspondingrelativistic electron dynamics, using which the underlying physics are discussed.
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| 8. |
- Ma, Guangjin, et al.
(författare)
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Relativistic high-order harmonic generation from laser plasmas using few-cycle laser pulses
- 2018
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Ingår i: Optics InfoBase Conference Papers. - : Optica Publishing Group. - 9781943580453
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Konferensbidrag (refereegranskat)abstract
- We investigate relativistic high-order harmonic generation from intense few-cycle laser and plasma interactions via particle-in-cell simulations. Differences of spectral and temporal structures in XUV beam resulted from few-cycle and non-few-cycle driver pulses are compared.
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| 9. |
- Ma, Guangjin, et al.
(författare)
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Waveform-dependent relativistic high-order harmonics and field-driven plasma surface dynamics
- 2019
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Ingår i: Ultrafast Optics 2019. - : SPIE. - 9781510635128 ; , s. 106-110
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Konferensbidrag (refereegranskat)abstract
- Attosecond XUV-pump XUV-probe experiments demand high brightness attosecond light source benefitting from state-of-the-art ultrashort ultraintense laser technology. Current most promising route towards high energy attosecond light source is through relativistic high-order harmonic generation from plasma surfaces. In this paper, we investigate waveform-dependent relativistic high-order harmonic generation from plasma surfaces, and use spectral interferometry to understand its generation process. The unique interpretation has allowed access to unrevealed temporal structure of the generated few-pulse attotrain with evidence supporting a well-isolated attosecond pulse. It also provides a way to measure field-driven plasma surface motion in its generation process.
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