Magnetically-Trapped Molecules Efficiently Loaded from a Molecular MOT

TL;DR

This paper demonstrates an efficient method to transfer cold molecules from a magneto-optical trap into a magnetic trap, achieving high transfer efficiency and long trap lifetime, paving the way for ultracold molecular research.

Contribution

The authors introduce a two-step cooling and pumping scheme that achieves 64% transfer efficiency from a molecular MOT to a magnetic trap, comparable to atomic experiments.

Findings

Achieved 64% transfer efficiency from MOT to magnetic trap.

Demonstrated magnetic trap lifetime over 1 second.

Enabled new studies of ultracold molecular collisions.

Abstract

We describe experiments demonstrating efficient transfer of molecules from a magneto-optical trap (MOT) into a conservative magnetic quadrupole trap. Our scheme begins with a blue-detuned optical molasses to cool SrF molecules to $\sim\!50$ $\mu$K. Next, we optically pump the molecules into a strongly-trapped sublevel. This two-step process reliably transfers $64\%$ of the molecules initially trapped in the MOT into the magnetic trap, comparable to similar atomic experiments. Once loaded, the magnetic trap is compressed by increasing the magnetic field gradient. Finally, we demonstrate a magnetic trap lifetime of over $1$ s. This opens a promising new path to the study of ultracold molecular collisions, and potentially the production of quantum-degenerate molecular gases.