Time-dependent perturbation theory beyond the dipole approximation for two-photon ionization of atoms

Wang, Mu-Xue; Liang, Hao; Xiao, Xue; Chen, Si-Ge; Peng, Liang-You

doi:10.1103/physreva.99.023407

Cited by 7 publications

(8 citation statements)

References 63 publications

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“…Likewise, the second-order perturbation theory can be used in the two-photon ionization process. [168,169] In the formulation of the Green's function, the two-photon transition amplitude beyond the dipole approximation can be shown to be [81] A…”

Section: Time-dependent Perturbation Methodsmentioning

confidence: 99%

“…By integrating over those asymmetric electron distribu-tions, one can obtain a net momentum of photoelectron along the direction of the light propagation, which comes from the linear photon-momentum partition between the photoelectrons and the residual ion. The photon-momentum transfer, which has been investigated respectively in the perturbative regime, [76][77][78][79][80][81] and in the tunneling regime, [77,79,[82][83][84][85][86][87][88][89][90][91][92][93][94][95] can be used to measure the radiation pressure and give insights into the breakdown of the dipole approximation.…”

Section: Introductionmentioning

confidence: 99%

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Review on non-dipole effects in ionization and harmonic generation of atoms and molecules*

et al. 2020

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In this review, we will focus on recent progress on the investigations of nondipole effects in few-electron atoms and molecules interacting with light fields. We first briefly survey several popular theoretical methods and relevant concepts in strong field and attosecond physics beyond the dipole approximation. Physical phenomena stemming from the breakdown of the dipole approximation are then discussed in various topics, including the radiation pressure and photon-momentum transfer, the atomic stabilization, the dynamic interference, and the high-order harmonic generation. Whenever available, the corresponding experimental observations of these nondipole effects are also introduced respectively in each topics.

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Section: Time-dependent Perturbation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Review on non-dipole effects in ionization and harmonic generation of atoms and molecules*

et al. 2020

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“…the ground state, conventional anisotropy and asymmetry parameters fail to provide comprehensive tools for the analysis of photoionization from atomic superposition states. For example, the simplest case of a competition between one-and two-photon ionization processes can be analyzed using asymmetry parameters if the atom is prepared in the ground state [20][21][22][23][24][25][26][27] . In contrast, these analysis tools are either not applicable or do not provide a straightforward interpretation for the same processes if the atom is in the superposition of two states.…”

Section: Openmentioning

confidence: 99%

“…Probing atoms and molecules in their ground or excited states with ultrashort laser pulses opens a new regime where several linear and nonlinear ionization pathways compete and interfere [20][21][22][23][24][25][26][27] . For example, it has been shown how the competition between resonant and nonresonant pathways depends on the pulse width 20 .…”

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confidence: 99%

Asymmetries in ionization of atomic superposition states by ultrashort laser pulses

Venzke

Becker

Jaroń-Becker

2020

Sci Rep

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Progress in ultrafast science allows for probing quantum superposition states with ultrashort laser pulses in the new regime where several linear and nonlinear ionization pathways compete. Interferences of pathways can be observed in the photoelectron angular distribution and in the past they have been analyzed for atoms and molecules in a single quantum state via anisotropy and asymmetry parameters. Those conventional parameters, however, do not provide comprehensive tools for probing superposition states in the emerging research area of bright and ultrashort light sources, such as free-electron lasers and high-order harmonic generation. We propose a new set of generalized asymmetry parameters which are sensitive to interference effects in the photoionization and the interplay of competing pathways as the laser pulse duration is shortened and the laser intensity is increased. The relevance of the parameters is demonstrated using results of state-of-the-art numerical solutions of the time-dependent Schrödinger equation for ionization of helium atom and neon atom.

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“…Over the last few decades, studies of nonlinear light-matter interaction have received much attention, both theoretically [1][2][3][4][5][6][7][8][9] as well as experimentally [10][11][12][13][14]. With the advancement of extreme ultraviolet (EUV) and X-ray light sources such as free-electron lasers (FELs) [15][16][17], energy restrictions of optical lasers have been removed and new opportunities to investigate ionization of inner-shell electrons of atoms and molecules arose [18].…”

Section: Introductionmentioning

confidence: 99%

Photoelectron Angular Distributions of Nonresonant Two-Photon Atomic Ionization Near Nonlinear Cooper Minima

Hofbrucker

Eiri

Volotka

et al. 2020

Atoms

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Photoelectron angular distributions of the two-photon ionization of neutral atoms are theoretically investigated. Numerical calculations of two-photon ionization cross sections and asymmetry parameters are carried out within the independent-particle approximation and relativistic second-order perturbation theory. The dependence of the asymmetry parameters on the polarization and energy of the incident light as well as on the angular momentum properties of the ionized electron are investigated. While dynamic variations of the angular distributions at photon energies near intermediate level resonances are expected, we demonstrate that equally strong variations occur near the nonlinear Cooper minimum. The described phenomena is demonstrated on the example of two-photon ionization of magnesium atom.

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Time-dependent perturbation theory beyond the dipole approximation for two-photon ionization of atoms

Cited by 7 publications

References 63 publications

Review on non-dipole effects in ionization and harmonic generation of atoms and molecules*

Review on non-dipole effects in ionization and harmonic generation of atoms and molecules*

Asymmetries in ionization of atomic superposition states by ultrashort laser pulses

Photoelectron Angular Distributions of Nonresonant Two-Photon Atomic Ionization Near Nonlinear Cooper Minima

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