Attosecond Transient Absorption Spectroscopy of doubly-excited states in helium

Argenti, Luca; Ott, Christian; Pfeifer, Thomas; Martín, Fernando

doi:10.1088/1742-6596/488/3/032030

Cited by 10 publications

(11 citation statements)

References 103 publications

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“…This protocol resembles the attosecond transient absorption employed to time-resolved core-level dynamics [37]. In fact, Pfeifer and co-workers [101] recently implemented the attosecond transient absorption analog of this experimental scheme and, indeed, interference fringes similar to those described here were observed and theoretically confirmed by one of us with full ab initio simulations [102].…”

Section: B Time-resolved Autoionization Resonances In Heliumsupporting

confidence: 63%

Photoionization of helium by attosecond pulses: Extraction of spectra from correlated wave functions

et al. 2013

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We investigate the photoionization spectrum of helium by attosecond XUV pulses both in the spectral region of doubly excited resonances as well as above the double ionization threshold. In order to probe for convergence, we compare three techniques to extract photoelectron spectra from the wave packet resulting from the integration of the time-dependent Schrödinger equation in a finite-element discrete variable representation basis. These techniques are projection on products of hydrogenic bound and continuum states, projection onto multichannel scattering states computed in a B-spline close-coupling basis, and a technique based on exterior complex scaling implemented in the same basis used for the time propagation. These methods allow one to monitor the population of continuum states in wave packets created with ultrashort pulses in different regimes. Applications include photo cross sections and anisotropy parameters in the spectral region of doubly excited resonances, time-resolved photoexcitation of autoionizing resonances in an attosecond pump-probe setting, and the energy and angular distribution of correlated wave packets for two-photon double ionization.

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Section: B Time-resolved Autoionization Resonances In Heliumsupporting

confidence: 63%

Photoionization of helium by attosecond pulses: Extraction of spectra from correlated wave functions

et al. 2013

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“…Very recently, the experimented reported by Ott et al 30 , in which the ultrafast TAS of Helium displayed characteristic beyond-SAE features, was theoretically analyzed in Ref. 31, utilizing an exact solution of the time-dependent Schrödinger equation, that cannot however be easily extended to larger systems. Finally, the above-mentioned experiment of Goulielmalkis et al 22 was analized with the model described in Ref.…”

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confidence: 99%

Simulating Pump–Probe Photoelectron and Absorption Spectroscopy on the Attosecond Timescale with Time‐Dependent Density Functional Theory

et al. 2013

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Molecular absorption and photo-electron spectra can be efficiently predicted with real-time time-dependent density-functional theory (TDDFT). We show here how these techniques can be easily extended to study timeresolved pump-probe experiments in which a system response (absorption or electron emission) to a probe pulse, is measured in an excited state. This simulation tool helps to interpret the fast evolving attosecond time-resolved spectroscopic experiments, where the electronic motion must be followed at its natural timescale. We show how the extra degrees of freedom (pump pulse duration, intensity, frequency, and time-delay), which are absent in a conventional steady state experiment, provide additional information about electronic structure and dynamics that improve a system characterization. As an extension of this approach, timedependent 2D spectroscopies can also be simulated, in principle, for large-scale structures and extended systems.

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“…The relative phase of the interfering pathways can be manipulated with a moderately strong NIR pulse, which enables control over the exact Fano line shape. A theoretical analysis revealed that the inversion of the Fano profile observed at a particular NIR intensity is expected to periodically repeat itself as a function of further increasing intensity [19].…”

Section: Review Of Recent Experimentsmentioning

confidence: 99%

Resolving intra-atomic electron dynamics with attosecond transient absorption spectroscopy

et al. 2013

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Attosecond transient absorption spectroscopy is a recent addition to the experimental tool set of attosecond science. This alloptical method measures different observables than the previously existing techniques based on electron and ion detection and overcomes several of their limitations. We review the present state-of-the-art of attosecond transient absorption experiments and theory. Applications cover the exploration of ultrafast electron dynamics in atoms as well as in solid-state systems. As an example we discuss the observation of transiently bound electron wavepacket dynamics in helium in more detail. This example illustrates how transient absorption spectroscopy can provide information that is fundamentally inaccessible to the techniques based on ionisation, namely dynamics occurring well below the ionisation threshold. Furthermore, we show that a model based on wavepacket interference and originally developed to explain modulations in the ion yield is not sufficient to explain the observed optical response of the system. The optical response on extremely short timescales and in systems exposed to strong laser fields is still not fully understood. This makes the method also attractive for fundamental studies. Furthermore, it is expected that the technique will also find future applications for studying molecular systems in gas phase, in solution, or as solids and will greatly benefit from the advances of ultrafast lasers with multi-100-W average power improving signal-to-noise ratio by many orders of magnitude in the near future. © 2013 Taylor & Francis

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Attosecond Transient Absorption Spectroscopy of doubly-excited states in helium

Cited by 10 publications

References 103 publications

Photoionization of helium by attosecond pulses: Extraction of spectra from correlated wave functions

Photoionization of helium by attosecond pulses: Extraction of spectra from correlated wave functions

Simulating Pump–Probe Photoelectron and Absorption Spectroscopy on the Attosecond Timescale with Time‐Dependent Density Functional Theory

Resolving intra-atomic electron dynamics with attosecond transient absorption spectroscopy

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