Characteristic Spectrum of Very Low-Energy Photoelectron from Above-Threshold Ionization in the Tunneling Regime

Wu, Chengyin; Yang, Yudong; Liu, Y. Q.; Gong, Qihuang; Wu, Mei‐Hwan; Liu, Xin; Hao, Xiaolei; Li, W. D.; He, X. T.; Chen, J.

doi:10.1103/physrevlett.109.043001

Cited by 128 publications

(138 citation statements)

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“…Holographic patterns are usually understood within the strong-field approximation (SFA) [1,2], or semiclassical models in which the influence of the ionic Coulomb potential on the dynamics of the ionized electron is fully neglected [11,12]. Recently, however, the Coulomb potential has been found to play an important role in the photoelectron spectra, leading to, e.g., an unexpected low-energy structure [17][18][19][20][21] and even a zero-energy structure [22,23]. The Coulomb potential also modifies the holographic patterns, resulting in, e.g., the reduced fringe spacing in the spiderlike holographic structure [6,7] and the appearance of the clear backscattering holography due to the Coulomb focusing [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Near-threshold photoelectron holography beyond the strong-field approximation

Lai¹,

Yu²,

Huang³

et al. 2017

Phys. Rev. A

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We study photoelectron angular distributions (PADs) near the ionization threshold with a newly developed Coulomb quantum-orbit strong-field approximation (CQSFA) theory. The CQSFA simulations exhibit an excellent agreement with the result from the time-dependent Schrödinger equation. We show that the low-energy fan-shaped pattern in the PADs corresponds to a subcycle time-resolved holographic structure and stems from the significant influence of the Coulomb potential on the phase of the forward-scattered electron trajectories, which affects different momenta and scattering angles unequally. Our work provides a direct explanation of how the fan-shaped structure is formed, based on the quantum interference of direct and forward-scattered orbits. Moreover, our work shows that the fan-shaped pattern can be used to extract information on the target structure, as the number of fringes in the PADs depends strongly on the symmetry of the electronic bound state.

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Section: Introductionmentioning

confidence: 99%

Near-threshold photoelectron holography beyond the strong-field approximation

Lai¹,

Yu²,

Huang³

et al. 2017

Phys. Rev. A

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“…4.3.2, the "ionization surprise" [48]-the LES [32,33] is investigated [1]. The explanation of the LES has triggered considerable theoretical effort in several research groups [47,1,73,74,75,24]. Analogous to the dynamics of a quantum wave packet, the collective behavior of trajectories explain the focusing of trajectories due to Coulomb effects.…”

Section: Resultsmentioning

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

Vrakking

et al. 2012

Springer Proceedings in 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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“…These include a series of energy peaks along the polarization axis below 0.1 U p called the low-energy structure (LES) [6,7,8], another structure at energies below the former referred to as the very-low-energy structure (VLES) [9,10], a fork-like structure off the polarization axis [11], and a V structure with the 'V' opening on either side of the origin along the axis perpendicular to the laser polarization [12]. All of these structures came unexpected because they are not afforded by a simple tunneling picture.…”

Section: Introductionmentioning

confidence: 99%

Unified description of low-order above-threshold ionization on and off axis

Becker

Milošević

2016

J. Phys.: Conf. Ser.

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View the article online for updates and enhancements.Related content Two-color above-threshold and two-photon sequential double ionization beyond the dipole approximation A N Grum-Grzhimailo, E V Gryzlova, E I Kuzmina et al. Phys. 48 151001) is revisited and extended. By considering the rescattering electron energies and angles at the classical cutoffs and the contributions of particular quantum-orbit solutions, it is shown that summing both the backward-and the forward-scattering contributions, within the low-frequency approximation, it is possible to reproduce the observed features of the ATI spectra both for low and high energies and both on and off the laser-polarization axis in the momentum plane. IntroductionAbove-threshold ionization (ATI) of rare-gas atoms had been considered a closed chapter of strong-field physics [1, 2, 3, 4] until, with the availability of mid-infrared lasers, unexpected structures in the low-energy velocity map (at energies well below the ponderomotive energy U p ) were observed [5]. These include a series of energy peaks along the polarization axis below 0.1 U p called the low-energy structure (LES) [6,7,8], another structure at energies below the former referred to as the very-low-energy structure (VLES) [9,10], a fork-like structure off the polarization axis [11], and a V structure with the 'V' opening on either side of the origin along the axis perpendicular to the laser polarization [12]. All of these structures came unexpected because they are not afforded by a simple tunneling picture. In calculations based on the time-dependent Schrödinger equation, they require the long-range Coulomb potential for their presence.In our recent papers [13,14,15], for a unified description of these low-energy effects we revisited the classical simple-man model and its quantum-mechanical implementation in terms of the improved strong-field approximation (ISFA), the low-frequency approximation (LFA) [16,17], and the quantum-orbit expansion [1,18]. It turned out that rescattering into states with low energy, especially forward scattering, generates all of the afore-mentioned effects. We have shown that the angle-dependent energy cutoffs of the various simple-man and quantum orbits are imprinted in the calculated velocity map [11,13,14,15]. The agreement with the various experimental data is good [11]. In particular, the recently observed V structure [12] is very well developed [14]. The afore-mentioned cut-off pattern is independent of the atomic

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Characteristic Spectrum of Very Low-Energy Photoelectron from Above-Threshold Ionization in the Tunneling Regime

Cited by 128 publications

References 31 publications

Near-threshold photoelectron holography beyond the strong-field approximation

Near-threshold photoelectron holography beyond the strong-field approximation

Trajectory-Based Coulomb-Corrected Strong Field Approximation

Unified description of low-order above-threshold ionization on and off axis

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