Trapping of molecular Oxygen together with Lithium atoms

TL;DR

This paper reports the first successful simultaneous deceleration and trapping of a cold mixture of atomic Lithium and molecular Oxygen, paving the way for low-temperature collision studies and sympathetic cooling.

Contribution

It introduces a novel method for decelerating and trapping a mixed atomic and molecular ensemble using magnetic traps and laser ablation.

Findings

Estimated $10^9$ trapped O$_2$ molecules and $10^5$ Li atoms.

Achieved background pressure limited lifetime of about 1 second.

Demonstrated initial steps towards sympathetic cooling of molecules.

Abstract

We demonstrate simultaneous deceleration and trapping of a cold atomic and molecular mixture. This is the first step towards studies of cold atom-molecule collisions at low temperatures as well as application of sympathetic cooling. Both atoms and molecules are cooled in a supersonic expansion and are loaded into a moving magnetic trap which brings them to rest via the Zeeman interaction from an initial velocity of 375 m/s. We use a beam seeded with molecular Oxygen, and entrain it with Lithium atoms by laser ablation prior to deceleration. The deceleration ends with loading of the mixture into a static quadrupole trap, which is generated by two permanent magnets. We estimate $10^9$ trapped O$_2$ molecules and $10^5$ Li atoms with background pressure limited lifetime on the order of 1 second. With further improvements to Lithium entrainment we expect that sympathetic cooling of molecules is within reach.