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Sensitivity of nonlinear photoionization to resonance substructure in collective excitation.

Mazza T, Karamatskou A, Ilchen M, Bakhtiarzadeh S, Rafipoor AJ, O'Keeffe P, Kelly TJ, Walsh N, Costello JT, Meyer M, Santra R - Nat Commun (2015)

Bottom Line: Resonant photoionization of atomic xenon was chosen as a case study.The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance.Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

View Article: PubMed Central - PubMed

Affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg, Germany.

ABSTRACT
Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

No MeSH data available.


Related in: MedlinePlus

Photon energy dependence of the calculated cross-sections.Photon energy dependence of the 1-photon (solid black line) and 2-photon (dotted red line) cross-sections calculated with the reduced model (a) and the full model (b). The scales on the left and right axes are chosen such that the maxima of the curves appear at the same height as the 1-photon cross-section peak. The dash–dotted blue lines represent the result for the 2-photon cross-section within the two-step model with one single intermediate resonance state. In the case of the reduced model, this approach captures the main features of the 2-photon cross-section, while for the full model it breaks down. The inset shows the full model 2-photon cross-section with two arrows indicating the energy position of the two underlying resonances calculated within the TDCIS model.
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f4: Photon energy dependence of the calculated cross-sections.Photon energy dependence of the 1-photon (solid black line) and 2-photon (dotted red line) cross-sections calculated with the reduced model (a) and the full model (b). The scales on the left and right axes are chosen such that the maxima of the curves appear at the same height as the 1-photon cross-section peak. The dash–dotted blue lines represent the result for the 2-photon cross-section within the two-step model with one single intermediate resonance state. In the case of the reduced model, this approach captures the main features of the 2-photon cross-section, while for the full model it breaks down. The inset shows the full model 2-photon cross-section with two arrows indicating the energy position of the two underlying resonances calculated within the TDCIS model.

Mentions: Having validated our full model by the comparison with experimental yields at two photon energies, we investigate the influence of collective effects on the 1- and 2-photon ionization cross-section over a wide photon energy range (Fig. 4). For the 1-photon cross-section, the broadening is due to the well-known broadening and blue shift of the giant resonance caused by the inclusion of coupling among different electron–hole states9, which is reproduced by our calculations (Fig. 4).


Sensitivity of nonlinear photoionization to resonance substructure in collective excitation.

Mazza T, Karamatskou A, Ilchen M, Bakhtiarzadeh S, Rafipoor AJ, O'Keeffe P, Kelly TJ, Walsh N, Costello JT, Meyer M, Santra R - Nat Commun (2015)

Photon energy dependence of the calculated cross-sections.Photon energy dependence of the 1-photon (solid black line) and 2-photon (dotted red line) cross-sections calculated with the reduced model (a) and the full model (b). The scales on the left and right axes are chosen such that the maxima of the curves appear at the same height as the 1-photon cross-section peak. The dash–dotted blue lines represent the result for the 2-photon cross-section within the two-step model with one single intermediate resonance state. In the case of the reduced model, this approach captures the main features of the 2-photon cross-section, while for the full model it breaks down. The inset shows the full model 2-photon cross-section with two arrows indicating the energy position of the two underlying resonances calculated within the TDCIS model.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403373&req=5

f4: Photon energy dependence of the calculated cross-sections.Photon energy dependence of the 1-photon (solid black line) and 2-photon (dotted red line) cross-sections calculated with the reduced model (a) and the full model (b). The scales on the left and right axes are chosen such that the maxima of the curves appear at the same height as the 1-photon cross-section peak. The dash–dotted blue lines represent the result for the 2-photon cross-section within the two-step model with one single intermediate resonance state. In the case of the reduced model, this approach captures the main features of the 2-photon cross-section, while for the full model it breaks down. The inset shows the full model 2-photon cross-section with two arrows indicating the energy position of the two underlying resonances calculated within the TDCIS model.
Mentions: Having validated our full model by the comparison with experimental yields at two photon energies, we investigate the influence of collective effects on the 1- and 2-photon ionization cross-section over a wide photon energy range (Fig. 4). For the 1-photon cross-section, the broadening is due to the well-known broadening and blue shift of the giant resonance caused by the inclusion of coupling among different electron–hole states9, which is reproduced by our calculations (Fig. 4).

Bottom Line: Resonant photoionization of atomic xenon was chosen as a case study.The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance.Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

View Article: PubMed Central - PubMed

Affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg, Germany.

ABSTRACT
Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

No MeSH data available.


Related in: MedlinePlus