Manipulating and measuring single atoms in the Maltese cross geometry

TL;DR

This paper presents optical trapping and measurement techniques for single rubidium atoms using a four-lens Maltese cross geometry, achieving high precision localization and comparable trap performance to simpler systems.

Contribution

It introduces a novel four-lens geometry for single-atom trapping that maintains high performance while providing additional optical access.

Findings

Achieved sub-wavelength 3D atom localization.

Measured trap lifetime, temperature, and transverse frequency.

Trap performance comparable to simpler optical systems.

Abstract

We describe optical methods for trapping, cooling, and observing single $^{87}$Rb atoms in a four-lens "Maltese cross" geometry (MCG). The use of four high numerical-aperture lenses in the cardinal directions enables efficient collection of light from non-collinear directions, but also restricts the optical access for cooling and optical pumping tasks. We demonstrate three-dimensional atom localization with sub-wavelength precision, and present measurements of the trap lifetime, temperature and transverse trap frequency in this geometry. We observe a trap performance comparable to what has been reported for single-atom traps with one- or two-lens optical systems, and conclude that the additional coupling directions provided by the MCG come at little cost to other trap characteristics.