Efficient loading of thulium atoms in a compact MOT for a transportable optical clock

TL;DR

This paper presents a compact and efficient method for trapping large numbers of ultracold thulium atoms in a magneto-optical trap, advancing the development of portable optical atomic clocks.

Contribution

The authors developed a compact vacuum chamber design that omits the Zeeman slower and enhances atom trapping efficiency for thulium atoms.

Findings

Achieved trapping of up to 13 million atoms in a compact MOT.

Increased atom number from 1 million to 6 million using Zeeman-like deceleration.

Demonstrated the setup's potential for portable high-performance optical clocks.

Abstract

We report on building of a compact vacuum chamber for spectroscopy of ultracold thulium and trapping of up to 13 million atoms. Compactness is achieved by obviating a classical Zeeman slower section and placing an atomic oven close to a magneto-optical trap (MOT), specifically at the distance of 11 cm. In this configuration, we significantly gained in solid angle of an atomic beam, which is affected by MOT laser beams, and reached 1 million atoms loaded directly in the MOT. By exploiting Zeeman-like deceleration of atoms with an additional laser beam, we increased the number of trapped atoms to 6 million. Then we gained an extra factor of 2 by tailoring the MOT magnetic field gradient with an additional small magnetic coil. Demonstrated results show great perspective of the developed setup for realizing a compact high-performance optical atomic clock based on thulium atoms.