Two-photon finite-pulse model for resonant transitions in attosecond experiments
Entity
UAM. Departamento de QuímicaPublisher
American Physical SocietyDate
2016-02-25Citation
10.1103/PhysRevA.93.023429
Physical Review A - Atomic, Molecular, and Optical Physics 93.2 (2016): 023429
ISSN
1050-2947 (print); 1094-1622 (online)DOI
10.1103/PhysRevA.93.023429Funded by
We acknowledge support from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant No. XCHEM 290853, the MINECO Project No. FIS2013-42002-R, the ERA-Chemistry Project No. PIM2010EEC-00751, the European grant MC-ITN CORINF, and the European COST Action XLIC CM1204.Project
info:eu-repo/grantAgreement/EC/FP7/290853; Gobierno de España. FIS2013-42002-R; info:eu-repo/grantAgreement/EC/FP7/264951Editor's Version
http://dx.doi.org/ 10.1103/PhysRevA.93.023429Subjects
Finite-pulse; Attosecond; QuímicaRights
© 2016 American Physical SocietyAbstract
We present an analytical model capable of describing two-photon ionization of atoms with attosecond pulses in the presence of intermediate and final isolated autoionizing states. The model is based on the finite-pulse formulation of second-order time-dependent perturbation theory. It approximates the intermediate and final states with Fano's theory for resonant continua, and it depends on a small set of atomic parameters that can either be obtained from separate ab initio calculations or be extracted from a few selected experiments. We use the model to compute the two-photon resonant photoelectron spectrum of helium below the N=2 threshold for the RABITT (reconstruction of attosecond beating by interference of two-photon transitions) pump-probe scheme, in which an XUV attosecond pulse train is used in association with a weak IR probe, obtaining results in quantitative agreement with those from accurate ab initio simulations. In particular, we show that (i) the use of finite pulses results in a homogeneous redshift of the RABITT beating frequency, as well as a resonant modulation of the beating frequency in proximity to intermediate autoionizing states; (ii) the phase of resonant two-photon amplitudes generally experiences a continuous excursion as a function of the intermediate detuning, with either zero or 2π overall variation
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Google Scholar:Jiménez-Galán, Álvaro
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Martín García, Fernando
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Argenti, Luca
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