Bright focused ion beam sources based on laser-cooled atoms

TL;DR

This paper reviews laser-cooled atom-based ion sources for focused ion beams, highlighting their high brightness and potential for nanotechnology applications, with recent demonstrations and future prospects.

Contribution

It provides a comprehensive overview of the principles, recent developments, and potential applications of laser-cooled atom ion sources in focused ion beam technology.

Findings

Laser-cooled atom ion sources achieve extremely high brightness.

Recent demonstrations include low energy ion microscopy with Li ions.

The field is rapidly evolving with promising new approaches.

Abstract

Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 uK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.