Strong-field ionization of Xe probed by femtosecond high-order harmonic absorption spectroscopy

ORAL

Abstract

Recent experiments on strong-field ionization of atoms and ions have led to conflicting conclusions regarding the existence of orbital alignment in the ionized species. Using table-top, femtosecond high-order harmonic absorption spectroscopy, we have measured the alignment of Xe$^{+}$ formed via strong-field ionization. High-order harmonics generated by focusing an intense 800 nm pulse into a Ne-filled capillary are spatially overlapped with an optical pump pulse in a sample gas cell before they are spectrally dispersed in an extreme ultraviolet spectrometer. Probing the transition from the 4$d$ core level to the $^{2}P_{3/2}$ state of Xe$^{+}$ at 55.4 eV yields a polarization anisotropy of 0.12 $\pm $ 0.01, in good agreement with the theoretical value of 0.1. This result suggests that strong-field ionization exclusively populates the $m_{J}=\pm $1/2 sub-levels in the Xe$^{+} \quad ^{2}P_{3/2}$ state.

*Supported by the NSF EUV ERC (0310717) and the LBNL LDRD program. R.S. was supported by DOE (DE-AC02-06CH11357).

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Authors

  • Zhi-Heng Loh

    • Department of Chemistry, University of California, Berkeley, CA 94720

  • Munira Khalil

    • Department of Chemistry, University of California, Berkeley, CA 94720

  • Raoul E. Correa

    • Department of Chemistry, University of California, Berkeley, CA 94720

  • Robin Santra

    • Argonne National Laboratory, Argonne, IL 60439

  • Stephen R. Leone

    • Departments of Chemistry and Physics, University of California, Berkeley, CA 94720
    • University of California, Berkeley
    • University of California, Berkeley \& LBNL