Focusing Helium Atom Beams Using Single Crystal Surfaces

Abstract

The manipulation of molecular beams has a history dating back to the days of Stern and Gerlach [1]. In the last few years, new techniques have become available so that the field of atom-optics has now emerged, with several potential areas of application. Classical methods of manipulation, using inhomogeneous fields, as well as recent approaches, using laser manipulation, require atoms with accessible electronic states and/or a permanent moment; that is, atoms that are generally regarded as reactive. Inert atoms, such as helium, demand an alternative approach. The motivation for manipulating beams of helium atoms lies in their use as a tool in the study of surfaces. Inertness is the property that confers value as a surface probe since, at thermal energies, scattering from a surface occurs without reaction or surface damage. This short review discusses recent progress in focussing thermal beams of helium atoms, where the principal aim is to create a micro-focused atom probe.