XFROG phase measurement of threshold harmonics in a Keldysh-scaled system

Power, E.; March, Anne Marie; Catoire, F.; Sistrunk, Emily; Krushelnick, K.; Agostini, Pierre; DiMauro, Louis F.

doi:10.1038/nphoton.2010.38

Cited by 79 publications

(60 citation statements)

References 25 publications

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“…In this case, its frequency distribution is associated with the spectrum of electromagnetic radiation emitted by the system [66]. Finally, it is tempting to point out the conceptual similarity between the Gabor transformation and the spectrogram measured in a pump-probe experiment [67][68][69], albeit there is no real probe pulse involved in the current theory.…”

Section: Time-dependent Approach To Resonances: Gabor Analysis Of mentioning

confidence: 96%

Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance

et al. 2015

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We present a detailed theoretical characterization of the two fundamental collective resonances underlying the xenon giant dipole resonance (GDR). This is achieved consistently by two complementary methods implemented within the framework of the configuration-interaction singles (CIS) theory. The first method accesses the resonance states by diagonalizing the many-electron Hamiltonian using the smooth exterior complex scaling technique. The second method involves a different application of the Gabor analysis to wave-packet dynamics. We identify one resonance at an excitation energy of 74 eV with a lifetime of 27 as and the second at 107 eV with a lifetime of 11 as. Our work provides a deeper understanding of the nature of the resonances associated with the GDR: a group of close-lying intrachannel resonances splits into two far-separated resonances through interchannel couplings involving the 4d electrons. The CIS approach allows a transparent interpretation of the two resonances as new collective modes. Due to the strong entanglement between the excited electron and the ionic core, the resonance wave functions are not dominated by any single particle-hole state. This gives rise to plasma-like collective oscillations of the 4d shell as a whole.

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Section: Time-dependent Approach To Resonances: Gabor Analysis Of mentioning

confidence: 96%

Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance

et al. 2015

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“…Thanks to its remarkable properties, HHG can be used as well to extract temporal and spatial information with both attosecond and subAngström resolution on the generating system [5]. Hence, HHG represents a considerable tool to enable scrutinizing the atomic world with its natural temporal and spatial scales [6][7][8][9][10][11].The intuitive physical mechanism behind HHG, for a single atom or molecule (referred to as 'single emitter'), has been well established in the so-called three steps or simple man's model [12][13][14]: in the first step, an electronic wave packet is released the continuum by tunnel ionization through the potential barrier as a consequence of the non-perturbative interaction of the single emitter with the laser field. In the second step, the emitted electronic wave packet propagates away from its ionic core in the continuum to be finally driven back when the laser electric field changes its sign.…”

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confidence: 99%

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confidence: 99%

High-order-harmonic generation by enhanced plasmonic near-fields in metal nanoparticles

et al. 2013

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We present theoretical investigations of high-order harmonic generation (HHG) resulting from the interaction of noble gases with localized surface plasmons. These plasmonic fields are produced when a metal nanoparticle is subject to a few-cycle laser pulse. The enhanced field, which largely depends on the geometrical shape of the metallic structure, has a strong spatial dependency. We demonstrate that the strong non-homogeneity of this laser field plays an important role in the HHG process and leads to a significant increase of the harmonic cut-off energy. In order to understand and characterize this new feature, we include the functional form of the laser electric field obtained from recent attosecond streaking experiments [F. Süßmann and M. F. Kling, Proc. of SPIE, Vol. 8096, 80961C (2011)] in the time dependent Schrödinger equation (TDSE). By performing classical simulations of the HHG process we show consistency between them and the quantum mechanical predictions. These allow us to understand the origin of the extended harmonic spectra as a selection of particular trajectory sets. The use of metal nanoparticles shall pave a completely new way of generating coherent XUV light with a laser field which characteristics can be synthesized locally. When matter, i.e. atoms or molecules, is exposed to short and intense laser radiation, non-linear phenomena are triggered as a consequence of this interaction. Amongst these phenomena, high-order harmonics generation (HHG) process [1, 2] has attracted considerable interests, since it is one of the most reliable pathways to generate coherent light from the ultraviolet (UV) to extreme ultraviolet (XUV) spectral range. As a result, HHG has proven to be a robust source for the generation of a PHz attosecond pulses train [3], that can be temporally confined to a single XUV attosecond pulse, now with kHz repetition rates [4]. Thanks to its remarkable properties, HHG can be used as well to extract temporal and spatial information with both attosecond and subAngström resolution on the generating system [5]. Hence, HHG represents a considerable tool to enable scrutinizing the atomic world with its natural temporal and spatial scales [6][7][8][9][10][11].The intuitive physical mechanism behind HHG, for a single atom or molecule (referred to as 'single emitter'), has been well established in the so-called three steps or simple man's model [12][13][14]: in the first step, an electronic wave packet is released the continuum by tunnel ionization through the potential barrier as a consequence of the non-perturbative interaction of the single emitter with the laser field. In the second step, the emitted electronic wave packet propagates away from its ionic core in the continuum to be finally driven back when the laser electric field changes its sign. In the final step, upon its return, the electronic wave packet may recombine with the core and the system relaxes the excess kinetic energy acquired by radiating a high-harmonic photon.In order to experimentally control the high harmonic ...

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“…(48), dW/dt = 0 leads to the SPA for the SFA in Eq. (35). The major purpose of the ITM is to study the tunneling probability through a time-dependent potential barrier.…”

Section: Imaginary Time Methodsmentioning

confidence: 99%

“…Experiments even show qualitative deviations from the predictions of the SFA. Such examples include the Coulomb-induced enhancement of the ionization rate [12,13,14,15], four-fold symmetry violation of angle-resolved photoelectron distributions in elliptically polarized fields [16,17], forward-backward symmetry violation of momentum distributions in few-cycle linearly polarized fields [18], a central minimum with a double "horn-like" structure in parallel momentum distributions [19,20,21,22,23,24] (though its mechanism is still in debate, see, e. g., [25,26]), a cusp-like peak at zero transverse momentum distribution [19,27], radial fanning-out structures in the near-threshold regime [28,29,30,31], the low energy structure (LES) [32,33], and the below-threshold high-harmonic generation due to the binding potential [34,35].…”

Section: Introductionmentioning

confidence: 99%

Trajectory-Based Coulomb-Corrected Strong Field Approximation

Yan

Popruzhenko

Bauer

2013

Springer Series in Chemical Physics

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The strong field approximation (SFA) is a widely used theoretical tool in the field of strong field physics and has been applied to various non-perturbative ionization processes. In particular, the SFA provides an intuitive semi-classical interpretation of strong field phenomena in terms of "quantum orbits". However, recent experimental results and ab initio simulations revealed deviations from the predictions of the SFA. We have developed a systematical extension of the SFA, the trajectory-based Coulomb-corrected strong field approximation (TCSFA), to explore Coulomb effects on strong field processes.We apply the TCSFA to the ionization of hydrogen-like systems in long-wavelength, linearly polarized laser fields. Photoelectron momentum spectra are explored by comparing results from the SFA, the TCSFA and solutions of the ab initio time-dependent Schrödinger equation (TDSE). It is shown that the TCSFA yields good agreement with exact TDSE results.The TCSFA provides unprecedentedly intuitive insights into the ionization dynamics. All spectral features can be interpreted in terms of trajectories. With the aid of the TCSFA, we successfully identify new types of quantum trajectories induced by the Coulomb potential and explain the origin of the recently discovered "low-energy structure" (LES). In addition, the interferences between different types of trajectories are explored to account for diverse complex interference patterns in spectra. Within the TCSFA, it is possible to distinguish the influences on interferences from real-space and under-barrier Coulomb corrections in classically forbidden regions. Z U S A M M E N FA S S U N G Die Starkfeldnäherung (engl. "strong field approximation" (SFA)) ist ein weit verbreitetes theoretisches Hilfsmittel auf dem Gebiet der Starkfeldphysik und wurde auf verschiedene nichtstörungstheo-retische Ionisationsprozesse angewandt. Die SFA ermöglicht eine intuitive, semi-klassische Interpretation von Starkfeldphänomenen mittels "Quantenbahnen". Neuere experimentelle Resultate und ab initio-Simulationen haben allerdings Abweichungen von den SFAVorhersagen aufgezeigt. Wir haben eine systematische Erweiterung der SFA entwickelt, die trajektorien-basierte Coulomb-korrigierte Starkfeldnäherung (engl. "trajectory-based Coulomb-corrected strong field approximation" (TCSFA)), um Coulomb-Effekte in Starkfeldprozessen zu untersuchen.iii Wir wenden die TCSFA auf die Ionisation von wasserstoffartigen Systemen in langwelligen, linearpolarisierten Laserfeldern an. Photoelektronenimpulsspektren werden untersucht, in dem Resultate der SFA, der TCSFA und Lösungen der ab initio zeitabhängigen Schrödinger-Gleichung (engl. "time-dependent Schrödinger equation" (TDSE)) verglichen werden. Es wird gezeigt, dass die TCSFA gute Übereinstimmung mit den exakten TDSE-Resultaten erzielt.Die TCSFA ermöglicht bisher unerreichte, intuitive Einsichten in die Ionisationsdynamik. Alle spektralen Eigenschaften können mittels Trajektorien interpretiert werden. Mit Hilfe der TCSFA kön-nen wir erfolgreich neue Typen von ...

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XFROG phase measurement of threshold harmonics in a Keldysh-scaled system

Cited by 79 publications

References 25 publications

Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance

Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance

High-order-harmonic generation by enhanced plasmonic near-fields in metal nanoparticles

Trajectory-Based Coulomb-Corrected Strong Field Approximation

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