Magneto-optical trapping of optically pumped metastable europium

TL;DR

This paper reports the successful laser cooling and magneto-optical trapping of europium atoms, achieving significant atom numbers and analyzing loss mechanisms, which advances the control of complex atomic species for quantum applications.

Contribution

It demonstrates magneto-optical trapping of europium via a quasi-cyclic transition, including analysis of loss rates and metastable state leakage, a novel achievement for this element.

Findings

Trapped up to 10^7 europium atoms.

Estimated two-body loss rate of 1×10^{-10} cm^3/s.

Observed leakage to metastable states enabling repumping.

Abstract

We demonstrate laser cooling and magneto-optical trapping of europium. The atoms are optically pumped to a metastable state and then loaded from an atomic-beam source via conventional Zeeman slowing and magneto-optical trapping techniques using a $J=13/2\leftrightarrow J=15/2$ quasi-cyclic transition. The trapped populations contained up to $1\times 10^7$ atoms, and a two-body loss rate is estimated as $1\times10^{-10}\,\mathrm{cm^3/s}$ from the non-exponential loss of atoms at high densities. We also observed leakage out of the quasi-cyclic transition to the two metastable states with $J=9/2$ and $11/2$, which is adequate to pump the laser-cooled atoms back to the $J=7/2$ ground state.