Efficiency of Dopant-Induced Ignition of Helium Nanoplasmas

TL;DR

This study investigates how different dopants induce ignition in helium nanoplasmas under intense laser pulses, revealing that dopant type, number of electrons donated, and location within the droplet significantly influence ignition efficiency.

Contribution

It provides a combined theoretical and experimental analysis of dopant-induced helium nanoplasma ignition, highlighting the importance of dopant properties and placement.

Findings

Ignition efficiency varies significantly with dopant species.

Dopant location within or on the droplet affects ignition.

Number of free electrons donated by dopants influences ignition success.

Abstract

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.