Observation of Bose-enhanced photoassociation products

TL;DR

This paper demonstrates Bose-enhanced Raman photoassociation to produce a large number of ultracold Sr2 molecules from a BEC, highlighting the role of Bose enhancement in molecular formation and potential for BEC-to-BEC conversion.

Contribution

It introduces Bose-enhanced STIRAP for efficient molecule production from a BEC and provides experimental measurements of Bose enhancement effects.

Findings

Produced over 8,000 ultracold molecules using Bose-enhanced Raman photoassociation

Measured transition Rabi frequency and confirmed Bose enhancement effects

Discussed feasibility of converting a BEC of atoms into a BEC of molecules

Abstract

We produce ${^{84}\mathrm{Sr}_2}$ molecules using Bose-enhanced Raman photoassociation. We apply the stimulated Raman adiabatic passage (STIRAP) technique on a Bose-Einstein condensate (BEC) to produce more than $8 \times 10^3$ ultracold molecules. This chemical reaction is only made possible because of the Bose enhancement of the optical transition dipole moment between the initial atomic state and an intermediate molecular state. We study the effect of Bose enhancement by measuring the transition Rabi frequency in a BEC and by comparing it with measurements for two atoms in sites of a Mott insulator. By breaking the dimers' bond and directly observing the separated atoms, we measure the molecular inelastic collision rate parameters. We discuss the possibility of applying Bose-enhanced STIRAP to convert a BEC of atoms into a BEC of molecules, and argue that the required efficiency for STIRAP is within experimental reach.