Probe of Multielectron Dynamics in Xenon by Caustics in High-Order Harmonic Generation.
We investigated the giant resonance in xenon by high-order harmonic generation spectroscopy driven by a two-color field. The addition of a nonperturbative second harmonic component parallel to the driving field breaks the symmetry between neighboring subcycles resulting in the appearance of spectral caustics at two distinct cutoff energies. By controlling the phase delay between the two color components it is possible to tailor the harmonic emission in order to amplify and isolate the spectral feature of interest. In this Letter we demonstrate how this control scheme can be used to investigate the role of electron correlations that give birth to the giant resonance in xenon. The collective excitations of the giant dipole resonance in xenon combined with the spectral manipulation associated with the two-color driving field allow us to see features that are normally not accessible and to obtain a good agreement between the experimental results and the theoretical predictions.
Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy.|Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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Faccialà
Center for Free-Electron Laser Science DESY, 22607 Hamburg, Germany.|ITAMP Harvard-Smithsonian Center for Astrophysics, 02138 Cambridge, Massachusetts, USA.
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Pabst
Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001 Rehovot, Israel.
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Bruner
Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy.|Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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Ciriolo
Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy.|Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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De Silvestri
Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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Devetta
Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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Negro
Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001 Rehovot, Israel.
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Soifer
Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy.|Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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Stagira
Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001 Rehovot, Israel.
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Dudovich
Istituto di Fotonica e Nanotecnologie-CNR, 20133 Milan, Italy.
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Vozzi