| 1. |
- Jimenez-Galan, A., et al.
(författare)
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Phase Measurement of a Fano Resonance Using Tunable Attosecond Pulses
- 2015
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 635, s. 092137-092137
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Konferensbidrag (refereegranskat)abstract
- We study photoionization of argon atoms close to the 3s(2)3p(6) -> 3s(1)3p(6)4p Fano resonance using an attosecond pulse train and a weak infrared probe field. An interferometric technique combined with tunable attosecond pulses allows us to determine the phase of the photoionization amplitude as a function of photon energy. We interpret the experimental results using an analytical two-photon model based on the Fano formalism and obtain quantitative agreement.
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| 2. |
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| 3. |
- Kotur, Marija, et al.
(författare)
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Spectral phase measurement of a Fano resonance using tunable attosecond pulses
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Electron dynamics induced by resonant absorption of light is of fundamental importance in nature and has been the subject of countless studies in many scientific areas. Above the ionization threshold of atomic or molecular systems, the presence of discrete states leads to autoionization, which is an interference between two quantum paths: direct ionization and excitation of the discrete state coupled to the continuum. Traditionally studied with synchrotron radiation, the probability for autoionization exhibits a universal Fano intensity profile as a function of excitation energy. However, without additional phase information, the full temporal dynamics cannot be recovered. Here we use tunable attosecond pulses combined with weak infrared radiation in an interferometric setup to measure not only the intensity but also the phase variation of the photoionization amplitude across an autoionization resonance in argon. The phase variation can be used as a fingerprint of the interactions between the discrete state and the ionization continua, indicating a new route towards monitoring electron correlations in time.
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| 4. |
- Louisy, Maïté, et al.
(författare)
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Compact single-shot d-scan setup for the characterization of few-cycle laser pulses
- 2017
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Ingår i: Applied Optics. - 1559-128X. ; 56:32, s. 9084-9089
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Tidskriftsartikel (refereegranskat)abstract
- We present a compact implementation of the ultrashort pulse measurement technique based on dispersion scans (d-scan), allowing single-shot measurement of few-cycle pulses. The main novelty in our design, making our setup extremely compact and simple, is the use, after a prism, of a spherical mirror in an off-axis geometry. The intentionally introduced strong astigmatism makes it possible to image the output of the crystal in one direction while focusing it in the other direction, resulting in the output face of the prism being imaged into a line in the second-harmonic crystal. The technique is validated by comparing measured dispersion scans, retrieved spectral phases and temporal profiles of this single-shot system with standard d-scan results.
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| 5. |
- Louisy, Maite, et al.
(författare)
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Gating attosecond pulses in a noncollinear geometry
- 2015
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Ingår i: Optica. - 2334-2536. ; 2:6, s. 563-566
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Tidskriftsartikel (refereegranskat)abstract
- The efficient generation of isolated attosecond pulses (IAPs), giving access to ultrafast electron dynamics in various systems, is a key challenge in attosecond science. IAPs can be produced by confining the extreme ultraviolet emission generated by an intense laser pulse to a single field half-cycle or, as shown recently, by employing angular streaking methods. Here, we experimentally demonstrate the angular streaking of attosecond pulse trains in a noncollinear geometry, leading to the emission of angularly separated IAPs. The noncollinear geometry simplifies the separation of the fundamental laser field and the generated pulses, making this scheme promising for intracavity attosecond pulse generation, thus opening new possibilities for high-repetition-rate attosecond sources. (C) 2015 Optical Society of America
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| 6. |
- Louisy, Maite
(författare)
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Generation of Ultrashort Pulses – From Femtoseconds to Attoseconds
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Electronic dynamics takes place on the attosecond timescale and can thus only be studied using a tool with attosecond temporal resolution. High harmonic generation (HHG) provides coherent attosecond pulses in the extreme ultraviolet spectral region. The work presented in this thesis focuses on generating and characterizing ultrashort femtosecond pulses and using them for HHG, together with a gating scheme, in order to produce isolated attosecond pulses (IAPs).The first part describes the work on the generation of high-energy, few-cycle femtosecond pulses using post-compression schemes, with emphasis on gas-filled, hollow-core capillary post-compression systems. General scaling laws for nonlinear optics in gases were identified.The second part focuses on the compression and characterization of ultra-broadband femtosecond pulses with emphasis on the dispersion scan (d-scan) technique for characterization of the pulses and on the stabilization of the carrier-to-envelope offset phase. Significant improvements were made in the d-scan technique, namely, a new, faster retrieval algorithm and a novel, compact, single-shot design.The last part deals with HHG. First, a pump-probe scheme called RABBIT (reconstruction of attosecond beating by interference of two-photon transitions) is described, with emphasis on its application to measure the phase across a Fano resonance. Then, a novel gating technique, called noncollinear optical gating, allowing the generation of several, spatially separated, synchronized IAPs, is presented together with its experimental demonstration.
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| 7. |
- Miranda, Miguel, et al.
(författare)
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Fast iterative retrieval algorithm for ultrashort pulse characterization using dispersion scans
- 2017
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Ingår i: Journal of the Optical Society of America B: Optical Physics. - 0740-3224. ; 34:1, s. 190-197
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Tidskriftsartikel (refereegranskat)abstract
- We present an iterative retrieval algorithm based on data constraint for ultrashort pulse characterization using dispersion scan (d-scan). The proposed algorithm is much faster and leads to a drastic reduction of retrieval times, but, compared to the standard algorithm, it performs less robustly in the retrieval of noisy d-scan traces. The algorithm is tested on several simulated cases and in two different experimental cases in the few-cycle regime.
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| 8. |
- Sytcevich, Ivan, et al.
(författare)
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Compact single-shot D-scan setup for the characterization of few-cycle laser pulses
- 2019
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Ingår i: 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2019. - 9781728104690
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Konferensbidrag (refereegranskat)abstract
- Ultrashort laser pulses have become an indispensable tool in physics, chemistry and engineering. Their numerous applications call for accurate and robust characterization techniques able to reliably retrieve the pulse's intensity profile. Different methods, such as FROG [1] or SPIDER [2] and their variants, have been developed in past decades and are now common in many laboratories. More novel approaches based on manipulating the light's spectral phase include techniques like MIIPS [3] and dispersion scan (d-scan) [4].
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