Optical pumping of a lithium atomic beam for atom interferometry

TL;DR

This paper demonstrates optical pumping of a lithium atomic beam to a specific hyperfine-Zeeman sublevel, enhancing atom interferometry precision by preparing atoms in a dark state with high efficiency.

Contribution

It introduces a method to optically pump lithium atoms into a single hyperfine-Zeeman sublevel using the D1-line, with characterization techniques for efficiency.

Findings

Achieved about 95% population transfer to the target sublevel.

Effective across a velocity range of 744-1520 m/s.

Magnetic dephasing confirms high pumping efficiency.

Abstract

We apply optical pumping to prepare the lithium beam of our atom interferometer in a single hyperfine-Zeeman sublevel: we use two components of the D1-line for pumping the 7Li atoms in a dark state F,mF=+2 (or -2) sublevel. The optical pumping efficiency has been characterized by two techniques: state-selective laser atom deflection or magnetic dephasing of the atom interferometer signals. The first technique has not achieved a high sensitivity, because of a limited signal to noise ratio, but magnetic dephasing signals have shown that about 95% of the population has been transferred in the aimed sublevel, with similar results for three mean velocities of the atomic beam covering the range 744-1520m/s.