Laser cooling of externally produced Mg ions in a Penning trap for sympathetic cooling of highly charged ions

TL;DR

This paper demonstrates laser cooling of externally produced Mg ions in a Penning trap, enabling potential sympathetic cooling of highly charged ions and precision spectroscopy.

Contribution

It introduces a method for laser cooling of Mg ions in a Penning trap with optical detection at the single ion level, advancing ion cooling techniques.

Findings

Observation of laser-induced fluorescence from Mg ions

Detection of ion crystals formation

Measurement of ion temperature and storage time

Abstract

We have performed laser cooling of Mg ions confined in a Penning trap. The externally produced ions were captured in flight, stored and laser cooled. Laser-induced fluorescence was observed perpendicular to the cooling laser axis. Optical detection down to the single ion level together with electronic detection of the ion oscillations inside the Penning trap have been used to acquire information on the ion storage time, ion number and ion temperature. Evidence for formation of ion crystals has been observed. These investigations are an important prerequisite for sympathetic cooling of simultaneously stored highly-charged ions and precision laser spectroscopy of forbidden transitions in these.