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arXiv · 2304.06374

Long-lasting XUV activation of helium nanodroplets for avalanche ionization

C. Medina·A. Ø. Lægdsmand·L. Ben Ltaief·Z. Hoque·A. H. Roos·M. Jurkovič·O. Hort·O. Finke·M. Albrecht·J. Nejdl·F. Stienkemeier·J. Andreasson·E. Klimešová·M. Krikunova·A. Heidenreich·M. Mudrich
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Abstract

We study the dynamics of avalanche ionization of pure helium nanodroplets activated by a weak extreme-ultraviolet (XUV) pulse and driven by an intense near-infrared (NIR) pulse. In addition to a transient enhancement of ignition of a nanoplasma at short delay times $\sim200$~fs, long-term activation of the nanodroplets lasting up to a few nanoseconds is observed. Molecular dynamics simulations suggest that the short-term activation is caused by the injection of seed electrons into the droplets by XUV photoemission. Long-term activation appears due to electrons remaining loosely bound to photoions which form stable `snowball' structures in the droplets. Thus, we show that XUV irradiation can induce long-lasting changes of the strong-field optical properties of nanoparticles, potentially opening new routes to controlling avalanche-ionization phenomena in nanostructures and condensed-phase systems.

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C. Medina, A. Ø. Lægdsmand, L. Ben Ltaief, Z. Hoque, A. H. Roos, M. Jurkovič, O. Hort, O. Finke, M. Albrecht, J. Nejdl, F. Stienkemeier, J. Andreasson, E. Klimešová, M. Krikunova, A. Heidenreich, M. Mudrich. 2023-04-13. Long-lasting XUV activation of helium nanodroplets for avalanche ionization. https://doi.org/10.1088/1367-2630/acd5f6

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