Laser Cooling of Molecular Anions

TL;DR

This paper proposes a laser cooling scheme for molecular anions, demonstrating through simulations that C₂⁻ can be cooled to below 1 mK rapidly using standard lasers, with potential applications in various fields.

Contribution

It introduces a feasible laser cooling method for molecular anions, specifically detailed for C₂⁻, including simulation results showing effective cooling to ultracold temperatures.

Findings

C₂⁻ can be cooled below 1 mK in tens of milliseconds

Standard lasers are sufficient for the cooling process

Both Sisyphus and Doppler cooling methods are effective

Abstract

We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics.