Helium nanodroplets irradiated by intense near-infrared laser pulses ignite and form highly ionized nanoplasmas even at laser intensities where helium is not directly ionized by the optical field, provided the droplets contain a few dopant atoms. We present a combined theoretical and experimental study of the He nanoplasma ignition dynamics for various dopant species. We find that the efficiency of dopants to ignite a nanoplasma in helium droplets strongly varies and mostly depends on (i) the pick-up process, (ii) the number of free electrons each dopant donates upon ionization, and remarkably, (iii) by the hitherto unexplored effect of the dopant location in or on the droplet.
@article{arxiv.1603.08659,
title = {Efficiency of Dopant-Induced Ignition of Helium Nanoplasmas},
author = {A. Heidenreich and B. Gruener and M. Rometsch and S. R. Krishnan and F. Stienkemeier and M. Mudrich},
journal= {arXiv preprint arXiv:1603.08659},
year = {2016}
}