1
|
Armstrong GSJ, Khokhlova MA, Labeye M, Maxwell AS, Pisanty E, Ruberti M. Dialogue on analytical and ab initio methods in attoscience. THE EUROPEAN PHYSICAL JOURNAL. D, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 2021; 75:209. [PMID: 34720730 PMCID: PMC8550504 DOI: 10.1140/epjd/s10053-021-00207-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/18/2021] [Indexed: 06/13/2023]
Abstract
The perceived dichotomy between analytical and ab initio approaches to theory in attosecond science is often seen as a source of tension and misconceptions. This Topical Review compiles the discussions held during a round-table panel at the 'Quantum Battles in Attoscience' cecam virtual workshop, to explore the sources of tension and attempt to dispel them. We survey the main theoretical tools of attoscience-covering both analytical and numerical methods-and we examine common misconceptions, including the relationship between ab initio approaches and the broader numerical methods, as well as the role of numerical methods in 'analytical' techniques. We also evaluate the relative advantages and disadvantages of analytical as well as numerical and ab initio methods, together with their role in scientific discovery, told through the case studies of two representative attosecond processes: non-sequential double ionisation and resonant high-harmonic generation. We present the discussion in the form of a dialogue between two hypothetical theoreticians, a numericist and an analytician, who introduce and challenge the broader opinions expressed in the attoscience community.
Collapse
Affiliation(s)
- Gregory S. J. Armstrong
- Centre for Theoretical Atomic, Molecular, and Optical Physics, Queen’s University Belfast, Belfast, BT7 1NN UK
| | - Margarita A. Khokhlova
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ UK
| | - Marie Labeye
- CNRS, PASTEUR, Département de chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, 75005 Paris, France
| | - Andrew S. Maxwell
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
| | - Emilio Pisanty
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Marco Ruberti
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ UK
| |
Collapse
|
2
|
Jin F, Yang H, Zhang H, Wang B, Yang W. Influence of polarization directions of the IR+XUV two-color laser fields on angle-resolved photoelectron energy spectrum. OPTICS EXPRESS 2021; 29:10726-10736. [PMID: 33820201 DOI: 10.1364/oe.420316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
By employing the frequency-domain theory, we investigate the influence of polarization directions on angle-resolved photoelectron energy spectrum in the above-threshold ionization (ATI) process of atoms exposed to the IR+XUV two-color laser fields, which shows the multiplateau structures. When the ionized electron is emitted along the IR laser's polarization direction, the width of each plateau keeps a certain energy range, and the jet structures and main lobes are determined by both the emission angle relative to the polarization direction of the XUV laser field and the number of the XUV photons absorbed by the electron. While when the ionized electron is emitted along the XUV laser's polarization direction, the width of each plateau depends on the polarization direction of the IR laser field, and the angular distribution of the ionized electron exhibits the isotropic characteristics. These results show that the ATI spectrum may be effectively controlled by changing the angle between the two laser fields' polarization directions.
Collapse
|
3
|
Xu TT, Gong WJ, Zhang LL, Qi Y. Frustrated nonsequential double ionization of Ar atoms in counter-rotating two-color circular laser fields. OPTICS EXPRESS 2020; 28:35168-35178. [PMID: 33182968 DOI: 10.1364/oe.409495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 10/27/2020] [Indexed: 06/11/2023]
Abstract
We theoretically investigate the frustrated double ionization (FDI) of Ar atoms with counter-rotating two-color circular (CRTC) laser fields using the three-dimensional (3D) classical ensemble method. Our results show that the FDI probability depends upon the intensity ratio of the CRTC laser fields. The FDI event accompanied with the recollision excitation with subsequent ionization is prevalent and three pathways exist in FDI processes driven by CRTC laser fields. The momentum distribution of a recaptured electron at the ionization time after recollision indicates that the momentum being close to the vector potential is a necessary condition for FDI events to occur. In addition, the recaptured electron most probably transitions to a Rydberg state of which the quantum number is ten in the CRTC fields.
Collapse
|
4
|
Jin F, Yang H, Wang B, Wei L, Wu H. Angular resolved above-threshold ionization spectrum of an atom in IR+XUV orthogonally polarized two-color laser fields. OPTICS EXPRESS 2019; 27:20754-20762. [PMID: 31510164 DOI: 10.1364/oe.27.020754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 04/29/2019] [Indexed: 06/10/2023]
Abstract
We investigate the above-threshold ionization (ATI) process of atoms exposed to the IR+XUV orthogonally polarized two-color laser fields by using the frequency-domain theory. It is shown that there exists a dip structure in each plateau of the angular resolved ATI spectrum. The dip structure in the first plateau is attributed to the fact that the electron cannot absorb one XUV photon when its emission direction is perpendicular to the XUV laser polarization, while the one in the second plateau is attributed to the coherent results of different channels. The emergence of dip structure is associated directly with the XUV laser field. Furthermore, by applying the saddle-point approximation, it is found that the fringes on the spectrum is caused by the interference of two trajectories for different saddle-points in the IR laser field. Finally, it is found that, in the high energy region, the probability of ATI spectrum is mainly determined by the XUV laser field, and the width of each plateau is mainly determined by the IR laser field; on the other hand, the ATI spectrum of the low energy region is only determined by the IR laser field.
Collapse
|
5
|
Tong A, Li Q, Ma X, Zhou Y, Lu P. Internal collision induced strong-field nonsequential double ionization in molecules. OPTICS EXPRESS 2019; 27:6415-6425. [PMID: 30876227 DOI: 10.1364/oe.27.006415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 01/30/2019] [Indexed: 06/09/2023]
Abstract
Using the classical ensemble method, we have investigated the alignment dependence of the correlated electron dynamics in strong-field nonsequential double ionization (NSDI) of diatomic molecules driven by linearly polarized laser pulses. Our numerical results show that the correlated electron pairs are more likely to emit into the same hemisphere (side-by-side emission) for the parallel aligned molecules at the small internuclear distance, in agreement with previous experimental results. Surprisingly, as the internuclear distance increases, this side-by-side emission is more prevalent for the perpendicularly aligned molecules. Back analyzing of the classical trajectories shows that a considerable part of the NSDI events for the parallel aligned molecules at the large internuclear distances occur through an internal collision, not the well-known recollision. In the internal collision induced NSDI, the first electron tunnels through the inner barrier from the up-field core, moves directly towards the other core, and kicks out the second electron. For this type of NSDI events, the electron pairs are more likely to emit into the opposite hemispheres and thus the correlated electron momentum spectrum exhibits a more dominant back-to-back behavior in the parallel aligned molecules.
Collapse
|
6
|
Ma X, Zhou Y, Chen Y, Li M, Li Y, Zhang Q, Lu P. Timing the release of the correlated electrons in strong-field nonsequential double ionization by circularly polarized two-color laser fields. OPTICS EXPRESS 2019; 27:1825-1837. [PMID: 30732230 DOI: 10.1364/oe.27.001825] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
With the semiclassical ensemble model, we systematically investigate the correlated electron dynamics in strong-field nonsequential double ionization (NSDI) by the counter-rotating circularly polarized two-color (CPTC) laser pulses. Our results show that the angular distributions of the electrons in NSDI sensitively depend on the intensity ratio of the CPTC laser fields. At the small ratio, the electron pairs emit with a relative angle of about 120°, and this angle shifts to 40° as the ratio increases and finally it exhibits a wide range distribution as the intensity ratio further increases. Back analysis of the NSDI trajectories shows that this behavior results from the relative-intensity-dependence of the release time of the electron pairs in the CPTC laser fields. The release times of the electron pairs are directly mapped to the angular distribution. Our results indicate that the emission times of the correlated electrons in NSDI can be controlled with the CPTC laser fields.
Collapse
|
7
|
Xu TT, Zhu QY, Chen JH, Ben S, Zhang J, Liu XS. Multiple recollisions in nonsequential double ionization by counter-rotating two-color circularly polarized laser fields. OPTICS EXPRESS 2018; 26:1645-1654. [PMID: 29402036 DOI: 10.1364/oe.26.001645] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 12/28/2017] [Indexed: 06/07/2023]
Abstract
With the three-dimensional (3D) classical ensemble method, we theoretically investigate the recollision dynamics in strong-field nonsequential double ionization (NSDI) of Ar by counter-rotating two-color circularly polarized laser fields. With the analysis of the NSDI trajectories, we find that not only multiple-recollision but also single-recollision processes occur in the double ionization events. Furthermore, the multiple-recollision and single-recollision processes both undergo the recollision-induced excitation with subsequent ionization (RESI) and recollision-induced ionization (RII). The angle between the momentum and the force of the laser field at the recollision moment can affect the times of the recollision.
Collapse
|
8
|
Li M, Zhang G, Kong X, Wang T, Ding X, Yao J. Dynamic Stark induced vortex momentum of hydrogen in circular fields. OPTICS EXPRESS 2018; 26:878-886. [PMID: 29401967 DOI: 10.1364/oe.26.000878] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
In this paper, we report our numerical simulation on the symmetry distortion and mechanism of the vortex-shaped momentum distribution of hydrogen atom by taking into account of the dynamic Stark effect. By deploying the strong field approximation (SFA) theory, we performed extensive simulation on the momentum pattern of hydrogen ionized by two time-delayed oppositely circularly polarized attosecond pulses. We deciphered that this distortion is originated from the temporal characteristics of the dynamic Stark phase which is nonlinear in time.
Collapse
|
9
|
Li N, Zhou Y, Ma X, Li M, Huang C, Lu P. Correlated electron dynamics in strong-field nonsequential double ionization of Mg. J Chem Phys 2017; 147:174302. [PMID: 29117686 DOI: 10.1063/1.5001668] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using the classical ensemble model, we systematically investigate strong-field nonsequential double ionization (NSDI) of Mg by intense elliptically polarized laser pulses with different wavelengths. Different from the noble atoms, NSDI occurs for Mg driven by elliptically and circularly polarized laser fields. Our results show that in elliptically and circularly polarized laser fields, the NSDI yield is sharply suppressed as the wavelength increases. Interestingly, the correlated behavior in the electron momentum spectra depends sensitively on the wavelengths. The corresponding electron dynamics is revealed by back tracing the classical trajectory.
Collapse
Affiliation(s)
- Ning Li
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yueming Zhou
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaomeng Ma
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Min Li
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Cheng Huang
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China
| | - Peixiang Lu
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
10
|
Zhou Y, Li M, Li Y, Tong A, Li Q, Lu P. Dissection of electron correlation in strong-field sequential double ionization using a classical model. OPTICS EXPRESS 2017; 25:8450-8458. [PMID: 28380956 DOI: 10.1364/oe.25.008450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recent experiments on strong-field sequential double ionization (SDI) have reported several observations which are regarded as evidence of electron correlation, querying the validity of the standard independent electron approximation for SDI. Here we theoretically study SDI with a classical ensemble model. The experimental results are well reproduced with this model. Back tracing of the ionization process shows that these results are ascribed to the subcycle ionization dynamics of the two electrons, not the evidences of the electron correlation in SDI. Thus, the previously reported observations are not enough to claim the breakdown of the independent electron approximation in SDI.
Collapse
|
11
|
Gao CZ, Dinh PM, Reinhard PG, Suraud E. Towards the analysis of attosecond dynamics in complex systems. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp00995j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We study from a theoretical perspective the ionization of molecules and clusters induced by irradiation of a combined two-color laser field consisting of a train of attosecond XUV pulses in the presence of an IR field.
Collapse
Affiliation(s)
- C.-Z. Gao
- Laboratoire de Physique Théorique
- Université de Toulouse
- CNRS
- UPS
- France
| | - P. M. Dinh
- Laboratoire de Physique Théorique
- Université de Toulouse
- CNRS
- UPS
- France
| | - P.-G. Reinhard
- Institut für Theoretische Physik
- Universität Erlangen
- Erlangen
- Germany
| | - E. Suraud
- Laboratoire de Physique Théorique
- Université de Toulouse
- CNRS
- UPS
- France
| |
Collapse
|
12
|
Nonsequential double ionization with mid-infrared laser fields. Sci Rep 2016; 6:37413. [PMID: 27857182 PMCID: PMC5114651 DOI: 10.1038/srep37413] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/27/2016] [Indexed: 11/29/2022] Open
Abstract
Using a full-dimensional Monte Carlo classical ensemble method, we present a theoretical study of atomic nonsequential double ionization (NSDI) with mid-infrared laser fields, and compare with results from near-infrared laser fields. Unlike single-electron strong-field processes, double ionization shows complex and unexpected interplays between the returning electron and its parent ion core. As a result of these interplays, NSDI for mid-IR fields is dominated by second-returning electron trajectories, instead of first-returning trajectories for near-IR fields. Some complex NSDI channels commonly happen with near-IR fields, such as the recollision-excitation-with-subsequent-ionization (RESI) channel, are virtually shut down by mid-IR fields. Besides, the final energies of the two electrons can be extremely unequal, leading to novel e-e momentum correlation spectra that can be measured experimentally.
Collapse
|
13
|
Lötstedt E, Kato T, Yamanouchi K. Decomposition of the configuration-interaction coefficients in the multiconfiguration time-dependent Hartree-Fock method. J Chem Phys 2016; 144:154111. [DOI: 10.1063/1.4947018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Erik Lötstedt
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tsuyoshi Kato
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kaoru Yamanouchi
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|
14
|
Li Y, Yu B, Tang Q, Wang X, Hua D, Tong A, Jiang C, Ge G, Li Y, Wan J. Transition of recollision trajectories from linear to elliptical polarization. OPTICS EXPRESS 2016; 24:6469-6479. [PMID: 27136838 DOI: 10.1364/oe.24.006469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Using a classical ensemble method, we revisit the topic of recollision and nonsequential double ionization with elliptically polarized laser fields. We focus on how the recollision mechanism transitions from short trajectories with linear polarization to long trajectories with elliptical polarization. We propose how this transition can be observed by meansuring the carrier-envelop-phase dependence of the correlated electron momentum spectra using currently available few-cycle laser pulses.
Collapse
|
15
|
Chen Y, Zhou Y, Li Y, Li M, Lan P, Lu P. The contribution of the delayed ionization in strong-field nonsequential double ionization. J Chem Phys 2016; 144:024304. [DOI: 10.1063/1.4939642] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yinbo Chen
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Yueming Zhou
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Yang Li
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Min Li
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Pengfei Lan
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
| | - Peixiang Lu
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
- Laboratory of Optical Information Technology, Wuhan Institute of Technology, Wuhan 430205, People’s Republic of China
| |
Collapse
|
16
|
Liu A, Thumm U. Criterion for Distinguishing Sequential from Nonsequential Contributions to the Double Ionization of Helium in Ultrashort Extreme-Ultraviolet Pulses. PHYSICAL REVIEW LETTERS 2015; 115:183002. [PMID: 26565465 DOI: 10.1103/physrevlett.115.183002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Indexed: 06/05/2023]
Abstract
We quantify sequential and nonsequential contributions in two-photon double ionization of helium atoms by intense ultrashort extreme-ultraviolet pulses with central photon energies ℏω_{ctr} near the sequential double-ionization threshold. If the spectrum of such pulses overlaps both the sequential (ℏω>54.4 eV) and nonsequential (ℏω<54.4 eV) double-ionization regimes, the sequential and nonsequential double-ionization mechanisms are difficult to distinguish. By tracking the double-ionization asymmetry in joint photoelectron angular distributions, we introduce the two-electron forward-backward-emission asymmetry as a measure that allows the distinction of sequential and nonsequential contributions. Specifically, for ℏω_{ctr}=50 eV pulses with a sine-squared temporal profile, we find that the sequential double-ionization contribution is the largest at a pulse length of 650 as, due to competing temporal and spectral constraints. In addition, we validate a simple heuristic expression for the sequential double-ionization contribution in comparison with ab initio calculations.
Collapse
Affiliation(s)
- Aihua Liu
- James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Uwe Thumm
- James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| |
Collapse
|
17
|
Zhang Z, Zhang J, Bai L, Wang X. Transition of correlated-electron emission in nonsequential double ionization of Ar atoms. OPTICS EXPRESS 2015; 23:7044-7052. [PMID: 25837049 DOI: 10.1364/oe.23.007044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Emission of the two electrons released from nonsequential double ionization of argon atoms is anticorrelated at lower laser intensities but is correlated at higher laser intensities. Such a transition is caused by the momentum change of recollision-induced-ionization (RII) electrons. At lower laser intensities, the Coulomb repulsion between the two RII electrons dominates the motion of electrons and pushes them leaving the laser field back-to-back. At higher laser intensities, the drift momentum obtained from the laser field dominates the motion of electrons and drives them leaving the laser field side-by-side.
Collapse
|