Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization
We present a theoretical study of ionization of the hydrogen atom due to an XUV pulse in the presence of an infrared (IR) laser with both fields linearly polarized in the same direction. In particular, we study the energy distribution of photoelectrons emitted perpendicularly to the polarization dir...
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todo:paper_24699926_v96_n2_p_Gramajo2023-10-03T16:41:35Z Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization Gramajo, A.A. Della Picca, R. Arbó, D.G. Atoms Electron emission Electron energy levels Electrons Ionization Neutron emission Photons Polarization Spectroscopy Time delay Trajectories Absorption and emissions Coherent superpositions Electron energy spectrum Interference patterns Intracycle interferences Polarization direction Semiclassical simulation Strong-field approximations Atom lasers We present a theoretical study of ionization of the hydrogen atom due to an XUV pulse in the presence of an infrared (IR) laser with both fields linearly polarized in the same direction. In particular, we study the energy distribution of photoelectrons emitted perpendicularly to the polarization direction. As we previously showed in Gramajo et al. [Phys. Rev. A 94, 053404 (2016)1050-294710.1103/PhysRevA.94.053404] for parallel emission, by means of a very simple semiclassical model which considers electron trajectories born at different ionization times, the electron energy spectrum can be interpreted as the interplay of intra- and intercycle interferences. However, contrary to the case of parallel emission the intracycle interference pattern stems from the coherent superposition of four electron trajectories giving rise to (i) interference of electron trajectories born during the same half cycle (intra-half-cycle interference) and (ii) interference between electron trajectories born during the first half cycle with those born during the second half cycle (inter-half-cycle interference). The intercycle interference is responsible for the formation of the sidebands. We also show that the destructive inter-half-cycle interference for the absorption and emission of an even number of IR laser photons is responsible for the characteristic sidebands in the perpendicular direction separated by twice the IR photon energy. This contrasts with the emission along the polarization axis (all sideband orders are present) since intra-half-cycle interferences do not exist in that case. The intracycle interference pattern works as a modulation of the sidebands and, in the same way, it is modulated by the intra-half-cycle interference pattern. We analyze the dependence of the energy spectrum on the laser intensity and the time delay between the XUV pulse and the IR laser. Finally, we show that our semiclassical simulations are in very good agreement with quantum calculations within the strong-field approximation and the numerical solution of the time-dependent Schrödinger equation, giving rise to nonzero emission, in contraposition to other theories. © 2017 American Physical Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_24699926_v96_n2_p_Gramajo |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Atoms Electron emission Electron energy levels Electrons Ionization Neutron emission Photons Polarization Spectroscopy Time delay Trajectories Absorption and emissions Coherent superpositions Electron energy spectrum Interference patterns Intracycle interferences Polarization direction Semiclassical simulation Strong-field approximations Atom lasers |
| spellingShingle |
Atoms Electron emission Electron energy levels Electrons Ionization Neutron emission Photons Polarization Spectroscopy Time delay Trajectories Absorption and emissions Coherent superpositions Electron energy spectrum Interference patterns Intracycle interferences Polarization direction Semiclassical simulation Strong-field approximations Atom lasers Gramajo, A.A. Della Picca, R. Arbó, D.G. Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization |
| topic_facet |
Atoms Electron emission Electron energy levels Electrons Ionization Neutron emission Photons Polarization Spectroscopy Time delay Trajectories Absorption and emissions Coherent superpositions Electron energy spectrum Interference patterns Intracycle interferences Polarization direction Semiclassical simulation Strong-field approximations Atom lasers |
| description |
We present a theoretical study of ionization of the hydrogen atom due to an XUV pulse in the presence of an infrared (IR) laser with both fields linearly polarized in the same direction. In particular, we study the energy distribution of photoelectrons emitted perpendicularly to the polarization direction. As we previously showed in Gramajo et al. [Phys. Rev. A 94, 053404 (2016)1050-294710.1103/PhysRevA.94.053404] for parallel emission, by means of a very simple semiclassical model which considers electron trajectories born at different ionization times, the electron energy spectrum can be interpreted as the interplay of intra- and intercycle interferences. However, contrary to the case of parallel emission the intracycle interference pattern stems from the coherent superposition of four electron trajectories giving rise to (i) interference of electron trajectories born during the same half cycle (intra-half-cycle interference) and (ii) interference between electron trajectories born during the first half cycle with those born during the second half cycle (inter-half-cycle interference). The intercycle interference is responsible for the formation of the sidebands. We also show that the destructive inter-half-cycle interference for the absorption and emission of an even number of IR laser photons is responsible for the characteristic sidebands in the perpendicular direction separated by twice the IR photon energy. This contrasts with the emission along the polarization axis (all sideband orders are present) since intra-half-cycle interferences do not exist in that case. The intracycle interference pattern works as a modulation of the sidebands and, in the same way, it is modulated by the intra-half-cycle interference pattern. We analyze the dependence of the energy spectrum on the laser intensity and the time delay between the XUV pulse and the IR laser. Finally, we show that our semiclassical simulations are in very good agreement with quantum calculations within the strong-field approximation and the numerical solution of the time-dependent Schrödinger equation, giving rise to nonzero emission, in contraposition to other theories. © 2017 American Physical Society. |
| format |
JOUR |
| author |
Gramajo, A.A. Della Picca, R. Arbó, D.G. |
| author_facet |
Gramajo, A.A. Della Picca, R. Arbó, D.G. |
| author_sort |
Gramajo, A.A. |
| title |
Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization |
| title_short |
Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization |
| title_full |
Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization |
| title_fullStr |
Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization |
| title_full_unstemmed |
Electron emission perpendicular to the polarization direction in laser-assisted XUV atomic ionization |
| title_sort |
electron emission perpendicular to the polarization direction in laser-assisted xuv atomic ionization |
| url |
http://hdl.handle.net/20.500.12110/paper_24699926_v96_n2_p_Gramajo |
| work_keys_str_mv |
AT gramajoaa electronemissionperpendiculartothepolarizationdirectioninlaserassistedxuvatomicionization AT dellapiccar electronemissionperpendiculartothepolarizationdirectioninlaserassistedxuvatomicionization AT arbodg electronemissionperpendiculartothepolarizationdirectioninlaserassistedxuvatomicionization |
| _version_ |
1782024899067379712 |