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

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, and M. Meyer

Phys. Rev. Lett. 118, 013002 – Published 5 January 2017

Abstract

Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate ${He}^{+} (3 p)$ 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.

Received 4 August 2016

DOI:https://doi.org/10.1103/PhysRevLett.118.013002

Physics Subject Headings (PhySH)

Angular momentum of light Atomic & molecular processes in external fields Electronic structure of atoms & molecules Multiphoton or tunneling ionization & excitation Optics & lasers Photoemission Stark effect

Atomic, Molecular & Optical

Authors & Affiliations

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, and M. Meyer¹

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