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arXiv · 2407.14227

Circular Dichroism in Multiphoton Ionization of Resonantly Excited Helium Ions near Channel Closing

Rene Wagner·Markus Ilchen·Nicolas Douguet·Philipp Schmidt·Niclas Wieland·Carlo Callegari·Zachary Delk·Alexander Demidovich·Michele Di Fraia·Jiri Hofbrucker·Michele Manfredda·Valerija Music·Oksana Plekan·Kevin C. Prince·Daniel E. Rivas·Marco Zangrando·Alexei N. Grum-Grzhimailo·Klaus Bartschat·Michael Meyer
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Abstract

The circular dichroism (CD) of photoelectrons generated by near-infrared (NIR) laser pulses using multiphoton ionization of excited He$^+$ ions in the 3p(m=+1) state. The ions were prepared by circularly polarized extreme ultraviolet (XUV) pulses. For circularly polarized NIR pulses co- and counter-rotating relative to the polarization of the XUV pulse, a complex variation of the CD is observed as a result of intensity- and polarization-dependent Freeman resonances, with and without additional dichroic AC-Stark shifts. The experimental results are compared with numerical solutions of the time-dependent Schr\"odinger equation to identify and interpret the pronounced variation of the experimentally observed CD.

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Rene Wagner, Markus Ilchen, Nicolas Douguet, Philipp Schmidt, Niclas Wieland, Carlo Callegari, Zachary Delk, Alexander Demidovich, Michele Di Fraia, Jiri Hofbrucker, Michele Manfredda, Valerija Music, Oksana Plekan, Kevin C. Prince, Daniel E. Rivas, Marco Zangrando, Alexei N. Grum-Grzhimailo, Klaus Bartschat, Michael Meyer. 2024-07-19. Circular Dichroism in Multiphoton Ionization of Resonantly Excited Helium Ions near Channel Closing. https://doi.org/10.1038/s41598-024-75459-1

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