Laser-assisted-autoionization dynamics of helium resonances with single attosecond pulses

Chu, Wei-Chun; Zhao, Song-Feng; Lin, C. D.

doi:10.1103/physreva.84.033426

Cited by 37 publications

(25 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1c). While the 2s2p2p 2 transition alone was previously used to control the transmission of helium 8,12,18 , here we measure and exploit the coupling of three autoionizing states for the reconstruction of the two-electron wave packet. The approximate time-dependent wave function |(t)exp(- 2s2p /2 t)|2s2p+a exp(- sp23+ /2 t)exp (-iυ(t))|sp 2,3+  is characterized by the relative phase υ(t) and amplitude a of the two contributing states 2s2p and sp 2,3+ .…”

mentioning

confidence: 99%

Reconstruction and control of a time-dependent two-electron wave packet

Ott

Kaldun

Argenti

et al. 2014

Nature

278

218

View full text Add to dashboard Cite

Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: The concerted motion of two or more bound electrons governs atomic 1 and molecular 2,3 non-equilibrium processes and chemical reactions. It is thus a long-standing scientific dream to measure and control the dynamics of two bound and correlated electrons in the quantum regime. At least two active electrons and a nucleus are required to address such quantum three-body problem 4 for which analytical solutions do not exist, a condition that is met in the helium atom. While attosecond dynamics were previously observed for singleactive electron/hole cases 5-7 , such time-resolved observation of two-electron motion thus far remained an unaccomplished challenge. Here, we measure a 1.2-femtosecond quantum beat among low-lying doubly-excited states in helium and use it to reconstruct a correlated two-electron wave packet. Our experimental method combines attosecond transientabsorption spectroscopy 5,7-9 at unprecedented high spectral resolution (20 meV s.d. near 60 eV) with an intensity-tuneable visible laser field to couple 10-12 the quantum states from the weak-field to the strong-coupling regime. Employing the Fano resonance as a phasesensitive quantum interferometer 13 , we demonstrate the coherent control of two correlated electrons, which form the basis of most covalent molecular bonds in nature. As we show, such multi-dimensional spectroscopy experiments provide benchmark data for testing fundamental few-body quantum-dynamics theory. They also light a route for site-specific measurement and control of metastable electronic transition states that are at the heart of fundamental reactions in chemistry and biology.Electrons are bound to atoms and molecules by the Coulomb force of the nuclei. Moving between atoms, they form the basis of the molecular bond. The same Coulomb force, however, acts repulsively between the electrons. This electron-electron interaction represents a major challenge in the understanding and modelling of atomic and molecular states, their structure and in particular their dynamics 2,3,14 . Here, we focus on the 1 P sp 2,n+ series 15 of doubly-excited states in helium below the N = 2 ionization threshold. They are excited by a single-photon transition from the 1 S 1s 2 ground state by the promotion of both electrons to at least principal quantum number n = 2. The states autoionize due to electron-electron interaction and their spectroscopic signature manifests as asymmetric non-Lorentzian line shapes. The latter were first observed in the 1930s 16 and attributed 17 , by Ugo Fano, to the quantum interference of bound states with the continuum to which they are coupled (Fig. 1c,d). The coupling is described by the configuration interaction V CI with the single-ionization continuum |1s,p, where one electron is in the 1s ground state and the other one is in the continuum with kinetic energy . The magnitude of V CI determines the lifetimes of the transiently bound states. In our case,...

show abstract

mentioning

confidence: 99%

Reconstruction and control of a time-dependent two-electron wave packet

Ott

Kaldun

Argenti

et al. 2014

Nature

278

218

View full text Add to dashboard Cite

show abstract

“…(1) is uniquely determined. The electron spectra for the two symmetries are P 1 ( 1 ) = |c 1 (t f )| 2 and P 2 ( 2 ) = |c 2 (t f )| 2 where t f is much larger than all the resonance lifetimes after the coefficients are stablized [16]. Alternative to Eq.…”

Section: -3mentioning

confidence: 99%

“…The conversion between the eigenstate coefficients and the bound-state and continuum-state coefficients has been detailed in Ref. [16] and is given bȳ…”

Section: -3mentioning

confidence: 99%

“…Most recently, the Fano line shapes modulated by time-delayed intense fields in transient absorption spectroscopy have been measured and analyzed [8,9], which has also brought to light the astounding potential to shape and to control the attosecond pulses [13]. In these studies and the related theoretical works, the dynamics of the Fano wave packet were mostly implemented as attosecond streaking [14,15] or resonant coupling [16][17][18][19] of the Fano states, if not carried out by ab initio calculations [20][21][22], which were numerically expensive and less intuitive. While the attention has been put on the directly measurable resonances under the dressing field, the properties of the dipole-forbidden resonances (DFRs) in the coupling were largely overlooked.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Probing dipole-forbidden autoionizing states by isolated attosecond pulses

2014

Self Cite

View full text Add to dashboard Cite

We propose a general technique to retrieve the information of dipole-forbidden resonances in the autoionizing region. In the simulation, a helium atom is pumped by an isolated attosecond pulse in the extreme ultraviolet (EUV) combined with a few-femtosecond laser pulse. The excited wave packet consists of the S-1, P-1, and D-1 states, including the background continua, near the 2s2p(P-1) doubly excited state. The resultant electron spectra with various laser intensities and time delays between the EUV and laser pulses are obtained by a multilevel model and an ab initio time-dependent Schrodinger equation calculation. By taking the ab initio calculation as a "virtual measurement," the dipole-forbidden resonances are characterized by the multilevel model. We found that in contrast to the common assumption, the nonresonant coupling between the continua plays a significant role in the time-delayed electron spectra, which shows the correlation effect between photoelectrons before they leave the core. This technique takes the advantages of ultrashort pulses uniquely and would be a timely test for the current attosecond technology

show abstract

“…To treat such problems theoretically, the numerical solution of the time-dependent Schrödinger equation has been carried out within the single electron approximation [18][19][20][21] . However, this approximation reveals itself inapplicable in the situation that is often encountered in quantum electronic dynamics of many-electron systems.…”

Section: Introductionmentioning

confidence: 99%

Transient electron dynamics of nitrogen molecule irradiated by femtosecond and XUV attosecond laser pulse train

et al. 2015

View full text Add to dashboard Cite

This study investigates the photoexcitation and ionization of a nitrogen molecule under ultrafast (femtosecond/attosecond) laser pulse irradiation. The real-time and real-space time-dependent density functional (TDDFT) is applied to describe the electron dynamics during the linear and nonlinear electron-photon interactions. The calculations describe well the behavior of the ionization process, and the results of ionization rates show good correspondence with the experimental results. In addition, the effects of near-infrared femtosecond laser pulse trains and the selected extreme ultraviolet attosecond laser pulse trains on electron dynamics are discussed. Theoretical results show that pulse number, laser frequency, and pulse delay are the key parameters for the control of electron dynamics including the electron excitation, energy absorption, electron density, and electron density oscillation.

show abstract

Laser-assisted-autoionization dynamics of helium resonances with single attosecond pulses

Cited by 37 publications

References 41 publications

Reconstruction and control of a time-dependent two-electron wave packet

Reconstruction and control of a time-dependent two-electron wave packet

Probing dipole-forbidden autoionizing states by isolated attosecond pulses

Transient electron dynamics of nitrogen molecule irradiated by femtosecond and XUV attosecond laser pulse train

Contact Info

Product

Resources

About