| 1. |
- Adamashvili, G T, et al.
(författare)
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Optical solitons in semiconductor quantum dot waveguides
- 2008
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 47:1, s. 113-117
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Tidskriftsartikel (refereegranskat)abstract
- A theory of self-induced transparency for a TM-mode propagating in a planar semiconductor waveguide sandwiched between two dielectric media is developed. A transition layer between the waveguide and one of the connected media is described using a model of a two-dimensional sheet of quantum dots. Explicit analytical expressions for the optical soliton in the presence of single-excitonic and biexcitonic transitions are obtained with realistic parameters which can be reached in current experiments.
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| 2. |
- Al-Mulla, Samir Yousif
(författare)
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Low-energy electron scattering from copper
- 2006
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 42:1, s. 11-14
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Tidskriftsartikel (refereegranskat)
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| 3. |
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| 4. |
- Alwahabi, Z. T., et al.
(författare)
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High resolution polarization spectroscopy and laser induced fluorescence of CO2 around 2 mu m
- 2007
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 42:1, s. 41-47
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Tidskriftsartikel (refereegranskat)abstract
- High resolution Infrared Polarisation Spectroscopy (IRPS) and Infrared Laser Induced Fluorescence (IRLIF) techniques were used to probe CO2/N-2 binary gas mixture at atmospheric pressure and ambient temperature. The probed CO2 molecules were prepared by laser excitation to an overtone and combination ro-vibrational state (12(0)1, J = 15) of CO2, centred at 4988.6612 cm(-1). IRPS and IRLIF line profiles were recorded for several CO2/N-2 binary mixtures. The observed IRLIF line shapes have the expected Lorentzian form while the observed IRPS line shapes are narrower by a factor of two than those recorded with the IRLIF and appear to have a Lorentzian-cubed profile. The recorded line profiles provide measurements of the pressure-broadening coefficient directly at atmospheric pressure. The Full-Width-Half-Maxima (FWHM) pressure broadening coefficients are measured, based on IRLIF, to be 0.2174 0.0092 cm(-1) atm(-1) and 0.1327 +/- 0.0077 cm(-1) atm(-1) for self- and N-2 collision broadening, respectively. The broadening coefficients obtained based on IRPS were measured to be similar to 8% larger than those obtained with IRLIF.
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| 5. |
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| 6. |
- Barnes, W. L., et al.
(författare)
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Solid-state single photon sources : light collection strategies
- 2002
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 18:2, s. 197-210
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Tidskriftsartikel (refereegranskat)abstract
- We examine the problem of efficiently collecting the photons produced by solid-state single photon sources. The extent of the problem is first established with the aid of simple physical concepts. Several approaches to improving the collection efficiency are then examined and are broadly categorized into two types. First are those based on cavity quantum dynamics, in which the pathways by which the source may emit a photon are restricted, thus channeling emission into one desired mode. Second are those where we try to reshape the free space modes into a target mode in an optimal way, by means of refraction, without fundamentally altering the way in which the source emits. Respectively, we examine a variety of microcavities and solid immersion lenses. Whilst we find that the micropillar microcavities offer the highest collection efficiency (similar to70%), choosing this approach may not always be appropriate due to other constraints. Details of the different approaches, their merits and drawbacks are discussed in detail.
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| 7. |
- Bergström, I, et al.
(författare)
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High-precision Mass Measurements of Hydrogen-Like 24Mg11+ and 26Mg11+ ions in a Pening Trap
- 2002
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 22:1, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- For the determination of the bound-electron g factor in hydrogen-like heavy ions the mass of the ion is needed at a relative uncertainty of at least 1 ppb. With the SMILETRAP Penning trap mass spectrometer at the Manne Siegbahn Laboratory in Stockholm several mass measurements of ions with even-even nuclei at this level of precision have been performed so far, exploiting the fact that the mass precision increases linearly with the ion charge. Measurements of masses of the hydrogen-like ions of the two Mg-isotopes 24Mg and 26Mg are reported. The masses of the hydrogen-like ions are 23.979011054(14) u and 25.976562354(34) u, corresponding to the atomic masses 23.985041690(14) u and 25.982592986(34) u, respectively. The possibility to use these two isotopes for the first observation of an isotope effect in the bound-electron g factor in hydrogen-like heavy ions is discussed.
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| 8. |
- Biémont, É., et al.
(författare)
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Decay of metastable states in NdII
- 2007
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 41:2, s. 211-219
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Tidskriftsartikel (refereegranskat)abstract
- The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements is illustrated in the case of Nd II. We have investigated the radiative decay of the low-lying metastable levels in Nd+ including the two levels 4f(4)(I-5) 5d K-6(11/2) and 4f(4)(I-5) 5d I-6(13/2). In these two particular cases, using di. erent theoretical approaches, we. nd that the decay is dominated by the M1 channels but that the E2 contributions are of the same order of magnitude. These levels have also been studied experimentally by lifetime measurements with the heavy ion storage ring CRYRING of Stockholm University. The difficulties encountered when performing such experiments are underlined and discussed.
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| 9. |
- Biemont, E, et al.
(författare)
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Lifetime measurements and calculations in LaI
- 2004
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 30:2, s. 157-162
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetime measurements have been performed, with a time-resolved laser-induced fluorescence technique, for 20 odd-parity levels of La I belonging to the configurations 5d(2)6p, 5d6s6p and 4f5d6s. The new results are compared with the few experimental data available in the literature and with theoretical calculations including configuration interaction effects. The agreement theory-experiment is generally satisfying but discrepancies are observed for some levels emphasizing the difficulty to get a reliable theoretical model in such a heavy and complex neutral element.
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| 10. |
- Biemont, E, et al.
(författare)
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Radiative lifetime measurements and oscillator strength determination for transitions in singly ionized praseodymium (Pr II)
- 2003
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 27:1, s. 33-41
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Tidskriftsartikel (refereegranskat)abstract
- New radiative lifetimes for 20 levels of Pr II have been measured using the time-resolved laser-induced fluorescence (LIF) technique. The combination of these experimental values with theoretical branching fractions (BF) obtained with the pseudo-relativistic Hartree-Fock (HFR) approach has allowed us to determine oscillator strengths and transition probabilities for about 150 lines appearing in the spectral region between 369.9 and 741.2 nm. A detailed discussion of our new results and comparisons with previous data are also given in the present paper.
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| 11. |
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| 12. |
- Boyle, Mark, et al.
(författare)
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Excitation dynamics of Rydberg states in C60
- 2005
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 36, s. 339-351
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Tidskriftsartikel (refereegranskat)abstract
- The electron and nuclear dynamics of C60 fullerenes irradiated with femtosecond laser pulses are investigated with photoelectron and photoion spectroscopy. The focus of this work is the detailed exploration of the population mechanism of Rydberg levels within the excitation process of neutral C60. The effect of excitation wavelength, intensity, chirp, and polarization on the kinetic energy distribution of photoelectrons in single-pulse experiments gives first insight into the underlying processes. In combination with time-resolved two-color pump-probe spectroscopy depending on either pump, or probe pulse intensity, a more complete picture of the interaction can be drawn. The results point towards a very interesting but nevertheless complex behavior including four steps: (i) non-adiabatic multielectron excitation of the HOMO (hu) → LUMO+1 (t1g) transition; (ii) thermalization within the hot electron cloud on a time scale below 100fs, followed by a coupling of energy to vibrational modes of the molecule via doorway state(s); (iii) population of electronically excited Rydberg states by multiphoton absorption, and (iv) single photon ionization from the excited Rydberg states. This excitation process results in a characteristic sequence of photoelectron lines in the photoemission spectra. The comparison of the experimental results with recent theoretical work gives convincing evidence that non-adiabatic multielectron dynamics (NMED) plays a key role for the understanding of the response of C60 to short-pulse laser radiation.
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| 13. |
- Bull, James N., et al.
(författare)
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Action spectroscopy of deprotomer-selected hydroxycinnamate anions
- 2021
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 75:2
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Tidskriftsartikel (refereegranskat)abstract
- Tandem ion mobility mass spectrometry-coupled laser excitation is used to record photodetachment, photoisomerization and photodepletion action spectra for a series of deprotomer-selected hydroxycinnamate anions, including deprotonated caffeic, ferulic and sinapinic acids. This molecular series accounts for most hydroxycinnainic moieties found in nature. Phenoxide deprotomers for para and ortho structural isomers have similar photodetachment action spectra that span the 350-460nm range with the maximum response occurring between 420 and 440 nm. None of the phenoxide deprotomers showed evidence for E -> Z photoisomerization. In contrast, photoexcitation of the carboxylate deprotomers of caffeic and ferulic acids and the meta-phenoxide deprotomer of caffeic acid initiates intramolecular proton transfer to give the para-phenoxide deprotomer. Photoexcitation of the carboxylate deprotomer of sinapinic acid and ortho-coumaric acid does not result in intramolecular proton transfer, presumably due to substantial barriers for rearrangement. For deprotonated meta-coumaric acid, interconversion between the phenoxide and carboxylate deprotomers occurs in the ion mobility spectrometer drift region where the effective ion temperature is T-eff approximate to 299 K.
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| 14. |
- Busto, David, et al.
(författare)
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Probing electronic decoherence with high-resolution attosecond photoelectron interferometry
- 2022
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 76:7
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Quantum coherence plays a fundamental role in the study and control of ultrafast dynamics in matter. In the case of photoionization, entanglement of the photoelectron with the ion is a well-known source of decoherence when only one of the particles is measured. Here, we investigate decoherence due to entanglement of the radial and angular degrees of freedom of the photoelectron. We study two-photon ionization via the 2s2p autoionizing state in He using high spectral resolution photoelectron interferometry. Combining experiment and theory, we show that the strong dipole coupling of the 2s2p and 2p2 states results in the entanglement of the angular and radial degrees of freedom. This translates, in angle-integrated measurements, into a dynamic loss of coherence during autoionization. Graphic Abstract: [Figure not available: see fulltext.]. © 2022, The Author(s).
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| 15. |
- Bylander, Jonas, 1978, et al.
(författare)
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Interference and correlation of two independent photons
- 2003
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6079 .- 1434-6060. ; 22, s. 295-301
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Tidskriftsartikel (refereegranskat)abstract
- Two independent photons, produced through the spontaneous emission of two separate emitters subject to uncorrelated dephasing processes, can display two-photon interference (i.e. coalescence into a two-photon state) when they are incident simultaneously on a beamsplitter, in a manner analogous to that of twin photons produced through degenerate parametric fluorescence. The presence of dephasing processes, however, reduces the interference contrast (i.e. the probability of coalescence), by the ratio of the coherence time to the lifetime of the emitter.
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| 16. |
- Carette, Thomas, et al.
(författare)
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Saturation spectra of low lying states of Nitrogen : reconciling experiment with theory
- 2010
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Ingår i: European Physical Journal D. - : Springer-Verlag New York. - 1434-6060 .- 1434-6079. ; 60:2, s. 231-242
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Tidskriftsartikel (refereegranskat)abstract
- The hyperfine constants of the levels 2p2(3P)3s 4PJ, 2p2(3P)3p 4Po J and 2p2(3P)3p 4Do J, deduced by Jennerich et al. [Eur. Phys. J. D 40, 81 (2006)] from the observed hyperfine structures of the transitions 2p2(3P)3s 4PJ → 2p2(3P)3p 4Po J and 2p2(3P)3s 4PJ → 2p2(3P)3p 4Do J recorded by saturation spectroscopy in the near-infrared, strongly disagree with the ab initio values of Jönsson et al. [J. Phys. B: At. Mol. Opt. Phys. 43, 115006 (2010)]. We propose a new interpretation of the recorded weak spectral lines. If the latter are indeed reinterpreted as crossover signals, a new set of experimental hyperfine constants is deduced, in very good agreement with the ab initio predictions.
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| 17. |
- Carturan, S., et al.
(författare)
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Formation of silver nanoclusters in transparent polyimides by Ag-K ion-exchange process
- 2007
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 42:2, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- Silver nanoclusters embedded in two transparent fluorinated polyimides, 4,4'-hexafluoroisopropylidene diphthalic anhydride - 2,3,5,6-tetramethyl paraphenylene diamine (6FDA-DAD) and 3,3',4,4' - biphenyltetracarboxylic acid dianhydride - 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane (BPDA-3F), have been produced by surface modification with KOH aqueous solution followed by K-assisted Ag doping and thermal reduction in hydrogen atmosphere. The reaction rate of the nucleophilic hydrolysis in KOH, studied by Fourier transform infrared spectroscopy (FT-IR) and Rutherford backscattering spectrometry (RBS), depends on the polyimide chemical structure. After ion-exchange in AgNO 3 solution and subsequent annealing, the polyimide structure recovery was monitored by FT-IR whereas the characteristic surface plasmon absorption band of silver nanoparticles was evidenced by optical absorption measurements. The structure of silver nanoclusters as related to size and size distribution in the different polyimide matrices was thoroughly investigated by Transmission electron microscopy (TEM) and X-ray diffraction (XRD). The collected data evidenced a uniform distribution of Ag clusters of nanometric size after thermal treatment at 300 °C in both polyimides. For the same ion-exchange treatment parameters and annealing temperature, XRD analyses evidenced the presence of crystallites with similar sizes. © EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2007.
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| 18. |
- Castellini, Alessia, et al.
(författare)
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Quantum plasmonics with multi-emitters: application to stimulated Raman adiabatic passage
- 2018
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6079 .- 1434-6060. ; 72:12
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: We construct a mode-selective effective model describing the interaction of the localised surface plasmon polaritons (LSPs) supported by a spherical metal nanoparticle (MNP) with N quantum emitters (QEs) in an arbitrary geometric arrangement. Simplifying previously presented procedures, we develop a formulation in which the field response in the presence of the MNP can be decomposed into orthogonal modes, expanding the Green tensor of the system in the spherical vector harmonics basis and using the generalized global Löwdin orthogonalization algorithm. We investigate the possibility of using the LSPs as mediators of an efficient control of population transfer between two QEs. We show that a Stimulated Raman Adiabatic Passage (STIRAP) configuration allows such a transfer via a decoherence-free dark state for a specific range of angular distances between the QEs, when they are located very close to the MNP. The transfer is otherwise blocked. We explain this blockade by the destructive superposition of all the plasmonic modes. Graphical abstract: [Figure not available: see fulltext.].
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| 19. |
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| 20. |
- De Sarlo, Luigi, et al.
(författare)
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From superradiant Rayleigh scattering to Bragg scattering
- 2005
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 32:2, s. 167-170
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of an experiment on light scattering from an elongated Bose-Einstein condensate interacting with far off resonant laser light. Due to superradiant Rayleigh scattering a coherent superposition of two atomic wavepackets with different momenta forms in the presence of a single laser beam. Varying the intensity of a weak counterpropagating laser beam we observe the transition from the pure superradiant regime to the Bragg scattering regime, where Rabi oscillations in a two-level system are observed. The process is limited by the decoherence between the two atomic wavepackets.
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| 21. |
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| 22. |
- Ding, Feng, 1970, et al.
(författare)
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Molecular dynamics study of the surface melting of iron clusters
- 2005
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Ingår i: European Physical Journal D : Atomic, Molecular and Optical Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 34:1-3, s. 275-277
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics simulations have been used to study the surface melting of iron clusters. It is found that, even when the temperature is several hundreds of Kelvin below the cluster melting point, the crystalline center of the cluster is surrounded by surface atoms that exhibit large amplitude diffusion from their original positions. This results in surface melting of the cluster.
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| 23. |
- Duan, Haiming, et al.
(författare)
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Initial growth of single-walled carbon nanotubes on supported iron clusters: a molecular dynamics study
- 2007
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Ingår i: EUROPEAN PHYSICAL JOURNAL D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 43:1-3, s. 185-188
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics simulations were used to study the initial growth of single-walled carbon nanotubes (SWNTs) on a supported iron cluster (Fe-50). Statistical analysis shows that the growth direction of SWNTs becomes more perpendicular to the substrate over time due to the weak interaction between carbon nanotube and the substrate. The diameter of the nanotube also increases with the simulation time and approaches the size of the supported iron cluster.
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| 24. |
- Ekman, Robin, 1991-, et al.
(författare)
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Short-scale quantum kinetic theory including spin-orbit interactions
- 2021
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Ingår i: European Physical Journal D. - : Springer. - 1434-6060 .- 1434-6079. ; 75:1
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Tidskriftsartikel (refereegranskat)abstract
- We present a quantum kinetic theory for spin-1/2 particles, including the spin-orbit interaction, retaining particle dispersive effects to all orders in ℏ, based on a gauge-invariant Wigner transformation. Compared to previous works, the spin-orbit interaction leads to a new term in the kinetic equation, containing both the electric and magnetic fields. Like other models with spin-orbit interactions, our model features "hidden momentum". As an example application, we calculate the dispersion relation for linear electrostatic waves in a magnetized plasma, and electromagnetic waves in a unmagnetized plasma. In the former case, we compare the Landau damping due to spin-orbit interactions to that due to the free current. We also discuss our model in relation to previously published works.
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| 25. |
- Ellmann, H., et al.
(författare)
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Investigation and characterization of a 3D double optical lattice
- 2003
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Ingår i: European Physical Journal D. - : EDP Sciences. - 1434-6060 .- 1434-6079. ; 22:3, s. 355-364
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed description of measurements performed with a novel double optical lattice setup. In this we trap two different cesium hyperfine ground states in separate periodic potentials. A detailed account of the technical solutions and its foundations are given. We demonstrate the possibility to modulate the relative spatial position of the lattices and perform a series of systematic measurements in order to investigate the static and dynamic properties of the double optical lattice system.
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| 26. |
- Ellmann, Harald, et al.
(författare)
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Temperatures in 3D optical lattices influenced by neighbouring transitions
- 2001
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Ingår i: European Physical Journal D. - 1434-6060 .- 1434-6079. ; 13:3, s. 379-384
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Tidskriftsartikel (refereegranskat)abstract
- A detailed experimental study of the steady-state temperature in a 3D optical lattice for cesium has been performed for a wide range of detunings. Specifically, we have investigated the situation with the cooling and trapping light detuned far red of a (J(g) --> J(e) = J(g) + 1)-transition, where the blue detuned interaction with a (J(g) --> J(e) = J(g))-transition can not be neglected. We find that the temperature scales with the optical potential due to the interaction with just the (J(g) --> J(e) = J(g) + 1)-transition. This indicates that blue Sisyphus cooling has essentially no effect on the dynamics of the system, when there exists a neighbouring red detuned transition.
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| 27. |
- Emile, Olivier, et al.
(författare)
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Mechanism of angular momentum transfer from microwaves to a copper ring
- 2016
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 70:8
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Tidskriftsartikel (refereegranskat)abstract
- In the exchange of orbital angular momentum between an electromagnetic wave and a copper ring we examine the origin of the Angular Momentum. We then investigate the transfer mechanism between the microwave and the object, and compare it with other mechanisms. We evidence a transfer mechanism based on the reflection of the electromagnetic field on the copper ring. In particular, at a microscopic scale, we show that the electromagnetic field induces alternative electric currents in the ring, with a small drift. Although little, the resistivity of copper leads to a force that rotates the ring. The estimation of the torque, which is of the order of 10(-8) Nm, is in good agreement with the experimental measurements. We also show that the transfer of electromagnetic orbital angular momentum to objects could be a way to measure the orbital angular momentum carried by electromagnetic fields, and we discuss possible applications.
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| 28. |
- Essén, Hanno, et al.
(författare)
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Drift velocity of charged particles in magnetic fields and its relation to the direction of the source current
- 2016
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Ingår i: European Physical Journal D. - : Springer. - 1434-6060 .- 1434-6079. ; 70:10
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Integrable motion of charged particles in magnetic fields produced by stationary currentdistributions is investigated. We treat motion in the magnetic field from an infinite flatcurrent sheet, a Harris current sheath, an infinite rectilinear current, and a dipole inits equatorial plane. We find that positively charged particles as a rule will drift inthe same direction as the current that is the source of the magnetic field in question.The conclusion is that charged particles moving under the influence of currentdistributions tend to enhance the current and that this indicates currentself-amplification. Graphical abstract: [Figure not available: see fulltext.]
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| 29. |
- Feifel, Raimund, et al.
(författare)
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From localised to delocalised electronic states in free Ar, Kr and Xe clusters
- 2004
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 30:3, s. 343-351
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Tidskriftsartikel (refereegranskat)abstract
- We present new results for the inner valence levels of clusters of the three inert gases Ar, Kr and Xe based on photoelectron spectroscopy studies. The inner valence levels are compared to the localised core levels and to the delocalised outer valence levels. This comparison shows a gradual change from a relatively localised behaviour for Ar inner valence 3s, over the intermediate case of Kr inner valence 4s, to a more delocalised behaviour for Xe inner valence 5s. This change correlates well with the ratio between the orbital sizes and the interatomic distances. The Kr4s intermediate case is found to exhibit characteristics of both localised and delocalised behaviour.
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| 30. |
- Fivet, V, et al.
(författare)
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Radiative lifetimes and transition probabilities in TaI
- 2006
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 37:1, s. 29-35
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes of 14 odd-parity Ta I levels, belonging to the 5d(3)6s6p and 5d(4)6p configurations in the energy range from 30 664 to 45 256 cm(-1). have been measured using the time-resolved laser-induced fluorescence technique. Extensive calculations, taking configuration interactions and corepolarisation effects into account, are able to reproduce in a satisfying way the available experimental results but suffer from the rather fragmentary knowledge of the level structure of this atom. New transition probabilities are deduced for a set of strong lines depopulating the levels investigated experimentally in the present work.
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| 31. |
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| 32. |
- Fülöp, Tünde, 1970, et al.
(författare)
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Relativistic laser plasma interactions
- 2017
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6079 .- 1434-6060. ; 71:11
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 33. |
- Genkin, Michael, et al.
(författare)
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Possibility of resonant capture of antiprotons by highly charged hydrogenlike ions
- 2009
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 51:2, s. 205-212
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Tidskriftsartikel (refereegranskat)abstract
- Recently, an experimetal setup was proposed by Lapierre et al (in Physics with ultra slow antiproton beams, AIP Conference Proceedings, edited by Y. Yamazaki and M. Wada (2005), vol. 793, p. 361) which would allow antiprotons and highly charged ions to collide repeatedly in an electron beam ion trap (EBIT) due to a nested trap configuration. As mentioned by the authors, such a setup may open the possibility to study antiproton capture into well-defined states through a resonant process which involves simultaneous electron excitation. In the present work, we give some theoretical estimations of the feasibility of that process.
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| 34. |
- Giacomelli, Luca, et al.
(författare)
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Comparison of neutron emission spectra for D and DT plasmas with auxiliary heating
- 2005
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Ingår i: The European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; :33, s. 235-241
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Tidskriftsartikel (refereegranskat)abstract
- The DT experimental campaign on JET (1997) represents a major step forward for neutronemission spectroscopy (NES) diagnostic through the high quality data collected by the Magnetic ProtonRecoil (MPR) spectrometer. These data for different DT plasma heating scenarios were analyzed here todetermine the underlying fuel ion populations which in turn were used to project the 2.5-MeV neutronemission spectra for deuterium plasmas. The results on neutron spectra for DT and D plasmas in thesame conditions were compared in order to determine the plasma information that could be expectedfrom NES diagnosis of D plasmas and the instrumental characteristics that would be required. FutureNES experiments would make dual sight line observations possible and the added diagnostic value is alsoassessed based on the present results.
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| 35. |
- Gorbach, A.V., et al.
(författare)
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Gap and out-gap breathers in a binary modulated discrete nonlinear Schrödinger model
- 2004
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 29:1, s. 77-93
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Tidskriftsartikel (refereegranskat)abstract
- We consider a modulated discrete nonlinear Schrödinger (DNLS) model with alternating on-site potential, having a linear spectrum with two branches separated by a 'forbidden' gap. Nonlinear localized time-periodic solutions with frequencies in the gap and near the gap - discrete gap and out-gap breathers (DGBs and DOGBs) - are investigated. Their linear stability is studied varying the system parameters from the continuous to the anti-continuous limit, and different types of oscillatory and real instabilities are revealed. It is shown, that generally DGBs in infinite modulated DNLS chains with hard (soft) non-linearity do not possess any oscillatory instabilities for breather frequencies in the lower (upper) half of the gap. Regimes of 'exchange of stability' between symmetric and antisymmetric DGBs are observed, where an increased breather mobility is expected. The transformation from DGBs to DOGBs when the breather frequency enters the linear spectrum is studied, and the general bifurcation picture for DOGBs with tails of different wave numbers is described. Close to the anti-continuous limit, the localized linear eigenmodes and their corresponding eigenfrequencies are calculated analytically for several gap/out-gap breather configurations, yielding explicit proof of their linear stability or instability close to this limit.
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| 36. |
- Greiner, Franko, et al.
(författare)
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Diagnostics and characterization of nanodust and nanodusty plasmas
- 2018
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Ingår i: European Physical Journal D. - : SPRINGER. - 1434-6060 .- 1434-6079. ; 72:5
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Tidskriftsartikel (refereegranskat)abstract
- Plasmas growing or containing nanometric dust particles are widely used and proposed in plasma technological applications for production of nano-crystals and surface deposition. Here, we give a compact review of in situ methods for the diagnostics of nanodust and nanodusty plasmas, which have been developed in the framework of the SFB-TR24 to fully characterize these systems. The methods include kinetic Mie ellipsometry, angular-resolved Mie scattering, and 2D imaging Mie ellipsometry to get information about particle growth processes, particle sizes and particle size distributions. There, also the role of multiple scattering events is analyzed using radiative transfer simulations. Computed tomography and Abel inversion techniques to get the 3D dust density profiles of the particle cloud will be presented. Diagnostics of the dust dynamics yields fundamental dust and plasma properties like particle charges and electron and ion densities. Since nanodusty plasmas usually form dense dust clouds electron depletion (Haynes effect) is found to be significant.
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| 37. |
- Gürkan, Nilhan, et al.
(författare)
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Toward a measurement of the effective gauge field and the Born-Huang potential with atoms in chip traps
- 2022
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Ingår i: European Physical Journal D. - : Springer Nature. - 1434-6060 .- 1434-6079. ; 76
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Tidskriftsartikel (refereegranskat)abstract
- We study magnetic traps with very high trap frequencies where the spin is coupled to the motion of the atom. This allows us to investigate how the Born–Oppenheimer approximation fails and how effective magnetic and electric fields appear as the consequence of the non-adiabatic dynamics. The results are based on exact numerical diagonalization of the full Hamiltonian describing the coupling between the internal and external degrees of freedom. The position in energy and the decay rate of the trapping states corresponding to the imaginary part of the resonances of this Hamiltonian are computed using the complex rotation method.
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| 38. |
- Hansen, Klavs, 1958, et al.
(författare)
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Obtaining colder ensembles of free clusters by using evaporation and recoil
- 2005
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Ingår i: Eur. Phys. J. D. - : Springer Science and Business Media LLC. - 1434-6060. ; 32, s. 339-345
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Tidskriftsartikel (refereegranskat)abstract
- We describe a theoretical model which treats the effects of evaporation-induced recoil on the mass and temperature distributions of a collimated beam of small neutral clusters emitted by a hot-nozzle source. The model incorporates two important consequences of in-flight cluster fragmentation processes. One is the well-known statistical evaporation of atoms and dimers accompanied by cluster size redistribution and cooling, and the other is the accompanying mechanical recoil of the fragments. We predict that the filtering effect introduced by cluster recoil can be used to an advantage by separating out the off-axis cluster population. This fraction will have a significantly narrower and colder distribution of internal temperatures than the on-axis ensemble.
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| 39. |
- Hansen, Klavs, 1958, et al.
(författare)
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The dissociation energy of V13+ and the consequences for radiative cooling
- 2005
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Ingår i: Eur. Phys. J. D. - : Springer Science and Business Media LLC. - 1434-6060. ; 34, s. 67-71
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Tidskriftsartikel (refereegranskat)abstract
- The dissociation energy of V13+ has been determined by comparison of the rates of sequential fragmentation, V13+→V 12+→V 11+, and single-step fragmentation of the first fragment, V12+→V 11+. The dissociation-energy value obtained as D=4.35(13) eV has implications for the amount of radiative cooling of the cluster derived form the data presented earlier [C. Walther et al., Phys. Rev. Lett. 83, 3816 (1999)] and is used to analyze additional results.
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| 40. |
- Hu, Wenxiang, et al.
(författare)
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A network of superconducting gravimeters as a detector of matter with feeble nongravitational coupling
- 2020
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 74:6
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Tidskriftsartikel (refereegranskat)abstract
- Hidden matter that interacts only gravitationally would oscillate at characteristic frequencies when trapped inside of Earth. For small oscillations near the center of the Earth, these frequencies are around 300 mu Hz. Additionally, signatures at higher harmonics would appear because of the non-uniformity of Earth's density. In this work, we use data from a global network of gravimeters of the International Geodynamics and Earth Tide Service (IGETS) to look for these hypothetical trapped objects. We find no evidence for such objects with masses on the order of 10(14) kg or greater with an oscillation amplitude of 0.1r(e). It may be possible to improve the sensitivity of the search by several orders of magnitude via better understanding of the terrestrial noise sources and more advanced data analysis.
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| 41. |
- Högberg, Björn, et al.
(författare)
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Anisotropically DNA-functionalized nanoparticle dimers
- 2007
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 43:1-3, s. 299-302
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembly of complex, non-periodic nanostructures can only be achieved by using anisotropic building-blocks. The building blocks need to have at least four bonds pointing in separate directions [J. Comput. Theor. Nanosci. 3, 391 (2006)]. We have previously presented a method for the synthesis of such building-blocks using DNA-functionalized gold nanoparticles. Here, we report on the progress in the experimental realization of this scheme. The first goal, in a process to make programmable self-assembly building-blocks using nanoparticles, is the production of dimers with different DNA-functions on the two component particles. We report on the fabrication of anisotropically functionalized dimers of nanoparticles of two different sizes. As a result of their anisotropy, these demonstrator building blocks can be made to assemble into spherical structures.
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| 42. |
- Ibrakovic, Neven, et al.
(författare)
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Achromatic dual-waveplate for inline two color high-order harmonic generation
- 2018
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 72:9
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: We propose a design of an achromatic dual-waveplate intended to align the polarization of orthogonal two-color pulses in an inline configuration. The waveplate acts as a half-waveplate for pulses with a carrier wavelength of 1300 nm over a bandwidth of 300 nm. For the second harmonic of the pulses the waveplate acts as a full-waveplate, centered at 650 nm with a bandwidth of 100 nm. By experimentally measuring the transmission of this optic when placed between two parallel linear polarizers we show that the polarization directions are aligned as expected. This experiment is then verified by calculating the transmission through the optic using Jones calculus. This waveplate could be useful in two-color experiments with few-cycle pulses, or pulses with a tunable wavelength, that need to be aligned with their second harmonics. Graphical abstract: [Figure not available: see fulltext.].
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| 43. |
- Jarnac, Amelie, et al.
(författare)
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Compression of TW class laser pulses in a planar hollow waveguide for applications in strong-field physics
- 2014
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 68:12
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate pulse post-compression of a TW class chirped pulse amplification laser employing a gas-filled planar hollow waveguide. A waveguide throughput of 80% is achieved for 50 mJ input pulse energy. Good focusability is found and after compression with chirped mirrors a pulse duration of sub-15 fs is measured in the beam center. Whereas a total energy efficiency of approximate to 70% should be achievable, our post-compressor currently delivers 20 mJ output pulse energy (approximate to 40% efficiency), mostly limited by apertures of chirped mirrors and vacuum windows. The viability of the planar hollow waveguide compression scheme for applications in strong-field physics is demonstrated by generating high-order harmonics in a pulsed Ar gas cell.
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| 44. |
- Jersblad, Johan, et al.
(författare)
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Anisotropic velocity distributions in 3D dissipative optical lattices
- 2003
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 22:3, s. 333-339
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Tidskriftsartikel (refereegranskat)abstract
- We present a direct measurement of velocity distributions in two dimensions by using an absorption imaging technique in a 3D near resonant optical lattice. The results show a clear difference in the velocity distributions for the different directions. The experimental results are compared with a numerical 3D semi-classical Monte-Carlo simulation. The numerical simulations are in good qualitative agreement with the experimental results.
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| 45. |
- Jersblad, J., et al.
(författare)
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Anisotropic velocity distributions in 3D dissipative optical lattices
- 2003
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Ingår i: European Physical Journal D. - : EDP Sciences. - 1434-6060 .- 1434-6079. ; 22:3, s. 333-339
-
Tidskriftsartikel (refereegranskat)abstract
- We present a direct measurement of velocity distributions in two dimensions by using an absorption imaging technique in a 3D near resonant optical lattice. The results show a clear difference in the velocity distributions for the different directions. The experimental results are compared with a numerical 3D semi-classical Monte-Carlo simulation. The numerical simulations are in good qualitative agreement with the experimental results.
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| 46. |
- Johansson, Allan, et al.
(författare)
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Two-color pump-probe experiments in helium using high-order harmonics
- 2003
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 22:1, s. 3-11
-
Tidskriftsartikel (refereegranskat)abstract
- A pump-probe technique has been applied for measuring the lifetimes and absolute photoionization cross-sections of excited He states. The 1s2p P-1 and 1s3p P-1 states of He are excited by using the 13th and the 14th harmonic, respectively, of a tunable 70 ps dye laser generated in a Kr gas jet. The states are ionized after a varying time delay, by absorption of probe photons with energies between 1.6 and 4.5 eV. Lifetimes of tau(1s2p) = 0.57 ns and tau(1s3p) = 1.76 ns are determined with a precision of about 15%. A significant enhancement of the number of ions present in the lifetime curves at zero time delay for pressures above 6 x 10(-5) mbar is attributed to direct two-photon ionization of He in combination with AC Stark broadening of the excited state and absorption of the XUV light in the medium. Absolute photoionization cross-sections from the He 1s2p P-1 and He 1s3p P-1 states in the threshold region are determined by measuring the saturation of the ionization process with a precision of similar to 25%. In addition, the variation of the relative orientation between the polarization vectors of the pump and probe beams enables the determination of partial photoionization cross-sections.
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| 47. |
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| 48. |
- Jonsell, Svante, et al.
(författare)
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A nonadiabatic semi-classical method for dynamics of atoms in optical lattices
- 2006
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Ingår i: European Physical Journal D. - Les Ulis : EDP Sciences. - 1434-6060 .- 1434-6079. ; 39:1, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- We develop a semi-classical method to simulate the motion of atoms in a dissipative optical lattice. Our method treats the internal states of the atom quantum mechanically, including all nonadiabatic couplings, while position and momentum are treated as classical variables. We test our method in the one-dimensional case. Excellent agreement with fully quantum mechanical simulations is found. Our results are much more accurate than those of earlier semi-classical methods based on the adiabatic approximation.
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| 49. |
- Kaja, Magdalena, et al.
(författare)
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Resonant laser ionization of neptunium: investigation on excitation schemes and the first ionization potential
- 2024
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Ingår i: EUROPEAN PHYSICAL JOURNAL D. - 1434-6060 .- 1434-6079. ; 78:5
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Tidskriftsartikel (refereegranskat)abstract
- The atomic structure of neptunium (Np) was investigated by two-step resonance ionization spectroscopy. The study involved exploring ground-state transitions as well as following transitions to high-lying states just below the ionization potential (IP) or auto-ionizing states above the IP. That resulted in the identification of two-step ionization schemes, suitable for trace analysis and nuclear structure investigations. The lifetimes of two excited states located at 25,342.48 cm(-1) and 25,277.64 cm(-1) were determined as 230(12) ns and 173(9) ns, respectively. Because of the absence of Rydberg series in wide-ranging spectra recorded, the first IP was determined through the field ionization of high-lying, weakly-bound states using a well-controlled static electric field. By applying the saddle-point model, an IP value of 50,535.54(15) cm(-1) [6.265608(19) eV] was derived. This value agrees with the current literature value of 50,535(2) cm(-1), while providing a more than ten times higher precision.
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| 50. |
- Karlsson, Hans O
(författare)
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Predissociation resonances in CO and IBr : Smooth exterior scaling combined with the discrete variable representation
- 2000
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Ingår i: European Physical Journal D. - : SPRINGER-VERLAG. - 1434-6060 .- 1434-6079. ; 11:2, s. 207-212
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Tidskriftsartikel (refereegranskat)abstract
- Smooth exterior scaling (SES) and the discrete variable representation (DVR) are combined to accurately compute predissociation resonances of a bound state non-adiabatically coupled to a dissociative state. For the CO(B(1)Sigma(+)-D('1)Sigma(+)) predissociation interaction good agreement is found with approaches based on optical potentials and complex scaling. The comparison is done both in the diabatic and the adiabatic representation. The effect of the coupling strength in the IBr (B(3)Pi(0+)-Y0(+)) predissociation interaction and the transition from the diabatic to the adiabatic picture was studied by computing resonances for coupling strengths from 50 cm(-1) up to 300 cm(-1). The transition from weak (diabatic) to strong (adiabatic) coupling was clearly seen. The intermediate case leads to a complicated resonance distribution. Comparison was made with recent studies using pump-probe spectroscopy [M. Shapiro, M.J.J. Vrakking, A. Stolow, J. Chem. Phys. 110, 2465 (1999)]. It was found that the overall features of the experiment could be explained from the resonance distribution, but for a detailed comparison more accurate potential energy surfaces and couplings are needed.
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