Circular Dichroism in Multiphoton Ionization of Resonantly Excited He^{+} Ions

M Ilchen; N Douguet; T Mazza; A J Rafipoor; C Callegari; P Finetti; O Plekan; K C Prince; A Demidovich; C Grazioli; L Avaldi; P Bolognesi; M Coreno; M Di Fraia; M Devetta; Y Ovcharenko; S Düsterer; K Ueda; K Bartschat; A N Grum-Grzhimailo; A V Bozhevolnov; A K Kazansky; N M Kabachnik; M Meyer

doi:10.1103/PhysRevLett.118.013002

Circular Dichroism in Multiphoton Ionization of Resonantly Excited He^{+} Ions

Phys Rev Lett. 2017 Jan 6;118(1):013002. doi: 10.1103/PhysRevLett.118.013002. Epub 2017 Jan 5.

Authors

M Ilchen^{1

2}, N Douguet³, T Mazza¹, A J Rafipoor¹, C Callegari⁴, P Finetti⁴, O Plekan⁴, K C Prince^{4

5

6}, A Demidovich⁴, C Grazioli⁴, L Avaldi⁷, P Bolognesi⁷, M Coreno⁷, M Di Fraia⁸, M Devetta⁹, Y Ovcharenko¹, S Düsterer¹⁰, K Ueda¹¹, K Bartschat³, A N Grum-Grzhimailo^{1

12}, A V Bozhevolnov¹³, A K Kazansky^{14

15

16}, N M Kabachnik^{1

12

16}, M Meyer¹

Affiliations

¹ European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld Hamburg, Germany.
² PULSE at Stanford, 2575 Sand Hill Road, Menlo Park, 94025 California, USA.
³ Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA.
⁴ Elettra-Sincrotrone Trieste, I-34149 Basovizza, Italy.
⁵ Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Area Science Park, I-34149 Trieste, Italy.
⁶ Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.
⁷ CNR Istituto Struttura della Materia, Via del Fosso del Cavaliere, 100-00133 Roma, Italy.
⁸ Department of Physics, University of Trieste, I-34128 Trieste, Italy.
⁹ Istituto di fotonica e nanotecnologie CNR-IFN, 20133 Milano, Italy.
¹⁰ Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22603 Hamburg, Germany.
¹¹ Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
¹² Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia.
¹³ Sankt Petersburg State University, Universitetskaya nab. 7/9, Sankt Petersburg 199164, Russia.
¹⁴ Departamento de Fisica de Materiales, UPV/EHU, E-20018 San Sebastian/Donostia, Spain.
¹⁵ IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao, Spain.
¹⁶ Donostia International Physics Center (DIPC), E-20018 San Sebastian/Donostia, Spain.

PMID: 28106422
DOI: 10.1103/PhysRevLett.118.013002

Abstract

Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate He^{+}(3p) resonance state. Applying angle-resolved electron spectroscopy, we find a large photon helicity dependence of the spectrum and the angular distribution of the electrons ejected from the resonance by NIR multiphoton absorption. The measured circular dichroism is unexpectedly found to vary strongly as a function of the NIR intensity. The experimental data are well described by theoretical modeling and possible mechanisms are discussed.