| 1. |
- Arnold, C. L., et al.
(författare)
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The ELI-ALPS secondary sources : A getaway to scientific excellence
- 2013
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Ingår i: 2013 Conference on Lasers and Electro-Optics, CLEO 2013. - 9781557529725 ; 2013
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Konferensbidrag (refereegranskat)abstract
- The essence of ELI-ALPS, the laser driven secondary sources ranging from X-ray and X-UV to THz with duration as short as tens of attoseconds, are designed to be available for users from 2016.
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| 2. |
- Kovács, K, et al.
(författare)
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Multi-parameter optimization of a loose focusing high flux high-harmonic beamline
- 2019
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 52:5, s. 055402-055402
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Tidskriftsartikel (refereegranskat)abstract
- We perform a multi-dimensional parameter scan in the generation of high-order harmonics, with the main purpose to find the macroscopic conditions that optimize the harmonic yield in a specific spectral domain, around 40 eV for this particular case. The scanned parameters are the laser pulse energy, gas pressure, interaction cell position relative to focus and the cell length, while the fixed parameters are chosen to model a loose focusing configuration which is used in many existing laboratories. We performed the simulations with a 3D non-adiabatic model complemented by a detailed analysis of the phase matching mechanisms involved in an efficient harmonic generation. Based on the results we identify a range of parameter combinations that lead to a high yield in the specified spectral domain. The method and results presented here can be the framework for the design and construction of high flux high-order harmonic generation beamlines.
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| 3. |
- Campi, F., et al.
(författare)
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The high intensity HHG beamline at lund laser
- 2014
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Ingår i: High Intensity Lasers and High Field Phenomena, HILAS 2014. - 9781557529954
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Konferensbidrag (refereegranskat)abstract
- We will present the new Lund HHG beamline designed for high photon flux, delivering pulse energies of more than 4 μJ per pulse in the spectral range from 20 eV to 45 eV. Focused XUV intensities above 1014 W/cm2 should become possible.
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| 4. |
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| 5. |
- Heyl, C. M., et al.
(författare)
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High-average power high-harmonic and attosecond sources : Status and prospects
- 2016
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Ingår i: Compact EUV and X-ray Light Sources, EUVXRAY 2016. - 9781943580095 ; Part F14-EUVXRAY 2016
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Konferensbidrag (refereegranskat)abstract
- Experiments employing extreme ultraviolet sources based on high harmonic generation often suffer from photon flux limitations. We discuss current status and prospects for scaling such sources to higher repetition rate, pulse energy and average power.
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| 6. |
- Heyl, C. M., et al.
(författare)
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Noncollinear optical gating - A method for intra-cavity single attosecond pulse generation?
- 2019
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Ingår i: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015. - 9781467374750
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Konferensbidrag (refereegranskat)abstract
- The process of high-order harmonic generation requires laser intensities around 1014 W/cm2, most easily reached with laser pulses of high energy, thus implicitly limiting the repetition rate of attosecond sources. A route towards multi-MHz attosecond sources relies on HHG inside a passive enhancement cavity [1]. Although successfully demonstrated for attosecond pulse trains, the generation of single attosecond pulses (SAPs) inside a cavity remains an unsolved challenge, mainly limited by dispersion management and out-coupling problems. We recently proposed a new gating concept for SAP generation [2], noncollinear optical gating (NOG) which has the potential to facilitate SAP gating and efficient out-coupling at once. Similar to the recently introduced attosecond lighthouse [3] NOG employs attosecond angular streaking [4] and combines this concept with noncollinear HHG, proposed earlier [5] as out-coupling method for intra cavity HHG.
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| 7. |
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| 8. |
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| 9. |
- Major, B., et al.
(författare)
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Macroscopic Optimization of High Harmonic Generation for High Power Laser Pulses
- 2016
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Ingår i: High Intensity Lasers and High Field Phenomena, HILAS 2016. - 9781943580095 ; Part F15-HILAS 2016
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Konferensbidrag (refereegranskat)abstract
- We study upscaling of gas high harmonic generation, to make efficient use of the ever increasing laser pulse powers. Loose focusing geometries optimizing phasematching are investigated and compared in HHG efficiency to shorter focusing arrangements.
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| 10. |
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| 11. |
- Manschwetus, B., et al.
(författare)
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Two-photon double ionization of neon studied with intense attosecond pulse trains
- 2016
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Ingår i: International Conference on Ultrafast Phenomena, UP 2016. - 9781943580187 ; Part F20-UP 2016
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Konferensbidrag (refereegranskat)abstract
- We focused an intense attosecond pulse train into a neon gas target and observed Ne2+ resulting from two-photon double ionization. By modifying the photon spectrum we find that the process is dominated by the sequential ionization via the Ne+ ion.
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| 12. |
- Manschwetus, B., et al.
(författare)
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Two-photon double ionization of neon using an intense attosecond pulse train
- 2016
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Ingår i: Physical Review A. - : American Physical Society (APS). - 2469-9926 .- 2469-9934. ; 93:6
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Tidskriftsartikel (refereegranskat)abstract
- We present a demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1μJ, a central energy of 35 eV, and a total bandwidth of ∼30 eV. The APT is focused by broadband optics in a neon gas target to an intensity of 3×1012Wcm−2. By tuning the photon energy across the threshold for the sequential process the double ionization signal can be turned on and off, indicating that the two-photon double ionization predominantly occurs through a sequential process. The demonstrated performance opens up possibilities for future XUV-XUV pump-probe experiments with attosecond temporal resolution in a photon energy range where it is possible to unravel the dynamics behind direct versus sequential double ionization and the associated electron correlation effects.
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| 13. |
- Lorek, Eleonora, et al.
(författare)
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High-Order Harmonic Generation and Plasmonics
- 2015
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Ingår i: Nano-Structures for Optics and Photonics : Optical Strategies for Enhancing Sensing, Imaging, Communication and Energy Conversion - Optical Strategies for Enhancing Sensing, Imaging, Communication and Energy Conversion. - Dordrecht : Springer Netherlands. - 9789401791328 - 9789401791335 ; , s. 531-531
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Bokkapitel (refereegranskat)abstract
- Attosecond pulses allow for imaging of very fast processes, like electron dynamics. Stockman et al. suggested to use these pulses in connection with a Photoemission electron microscope (PEEM) to study the ultrafast dynamics of plasmons (Stockman et al. Nat Photonics 1:539–544, 2007). For efficient plasmon studies, the repetition rate of the attosecond pulses used needs to be higher than a few kHz (Mikkelsen et al. Rev Sci Instrum 80:123703, 2009). Attosecond pulses are produced in a process called high-order harmonic generation (HHG) (Paul et al. Science 292(5522):1689–1692, 2001; Ferray et al. J Phys B At Mol Opt Phys 21:L31–L35, 1988). In HHG, a strong laser field allows an electron to tunnel out, get accelerated and recombine with a high kinetic energy resulting in extreme ultraviolet attosecond pulses. The large intensity needed to drive the process normally limits the repetition rate of the laser to a few kHz. Using a tight focusing scheme (Heyl et al. Phys Rev Lett 107:033903, 2011; Vernaleken et al. Opt Lett 36:3428–3430, 2011), we, however, generate harmonics at a repetition rate of 200 kHz, both with a commercial turn-key laser and with an advanced laser system. Suitable nanostructures for a strong field enhancement are produced in-house and the field enhancement is studied with PEEM in a non-time resolved manner. With high-order harmonics produced at a high repetition rate, we hope to be able to follow also the ultrafast dynamics of plasmons in these structures (Mårsell et al. Ann der Phys 525:162–170, 2013).
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| 14. |
- Maclot, Sylvain, et al.
(författare)
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Dissociation dynamics of the diamondoid adamantane upon photoionization by XUV femtosecond pulses
- 2020
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a photodissociation study of the diamondoid adamantane using extreme ultraviolet femtosecond pulses. The fragmentation dynamics of the dication is unraveled by the use of advanced ion and electron spectroscopy giving access to the dissociation channels as well as their energetics. To get insight into the fragmentation dynamics, we use a theoretical approach combining potential energy surface determination, statistical fragmentation methods and molecular dynamics simulations. We demonstrate that the dissociation dynamics of adamantane dications takes place in a two-step process: barrierless cage opening followed by Coulomb repulsion-driven fragmentation.
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| 15. |
- Matyschok, J., et al.
(författare)
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Compact, few-cycle OPCPA system with ultralow CEP noise
- 2013
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Ingår i: Advanced Solid State Lasers, ASSL 2013. - 9781557529824
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Konferensbidrag (refereegranskat)abstract
- A compact, high-repetition rate OPCPA system with CEP-stable 6.3 fs pulses duration and 10 μJ of pulse energy is presented together with results from numerical simulations. First results of high harmonic generation will be shown.
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| 16. |
- Matyschok, J., et al.
(författare)
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Ultra-stable fiber pumped CEP-stabilized dual stage OPCPA system
- 2013
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Ingår i: 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC. - 9781479905942
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Konferensbidrag (refereegranskat)abstract
- For the generation of intense few-cycle laser pulses with stable carrier envelope phase (CEP), the approach of optical parametric chirped pulse amplification (OPCPA) is well established. In this contribution we present a compact and robust CEP-stable OPCPA system emitting pulses with energy above 10 μJ at 200 kHz repetition rate and pulse durations of 6.3 fs. Additionally, we present the results of (2+1)-dimensional numerical simulations [1] for a better understanding of the parametric amplification process.
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| 17. |
- Miranda, M., et al.
(författare)
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Generation and spatiotemporal characterization of ultrashort vortex pulses
- 2019
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Ingår i: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015. - 9781467374750
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Konferensbidrag (refereegranskat)abstract
- Some light beams rotate as they propagate. If it is not the polarization vector, but the phase structure that rotates, the beam is said to carry orbital angular momentum (OAM). Such beams exhibit a helical phase front, where the phase rotates around a symmetry center. Because the phase in the center is undefined (and the intensity there is therefore zero), it is often termed a phase singularity or optical vortex by analogy to superfluidic vortices. Vortex beams [1,2] and more specifically ultrashort (few cycle) vortex pulses [3] have recently attracted strong interest.
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