2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/224427Doping a helium nanodroplet with a tiny xenon cluster of a few atoms only, sparks complete ionization of the droplet at laser intensities below the ionization threshold of helium atoms. As a result, the intrinsically inert and transparent droplet turns into a fast and strong absorber of infrared light. Microscopic calculations reveal a two-step mechanism to be responsible for the dramatic change: Avalanche-like ionization of the helium atoms on a femtosecond time scale, driven by field ionization due to the quickly charged xenon core is followed by resonant absorption enabled by an unusual cigar-shaped nanoplasma within the droplet.4 pages, 4 figuresAtomic and Molecular ClustersPlasma PhysicsLaser-driven nanoplasmas in doped helium droplets: Local ignition and anisotropic expansiontext