Engineering the sub-Doppler force in molecular magneto-optical traps

TL;DR

This paper proposes a theoretical method to engineer sub-Doppler effects in molecular magneto-optical traps, enabling cooling instead of heating, with simulations indicating promising temperature and density results for CaF molecules.

Contribution

It introduces a novel approach to control sub-Doppler effects in molecular MOTs, improving cooling performance over existing methods.

Findings

Achieved cooling in molecular MOTs through engineered sub-Doppler effects.

Simulated temperature of 40 μK and density of 4×10^8 cm^-3 for CaF molecules.

Estimated trapping of 10^5 molecules in the proposed scheme.

Abstract

Current dual-frequency magneto-optical traps for ultracold molecules are plagued by sub-Doppler heating effects, making them vastly inferior to standard atomic MOTs. Here we demonstrate theoretically that the sub-Doppler effects in such a MOT can be engineered to provide cooling instead of heating. We give an intuitive picture how to achieve such cooling and show the cooling and trapping force results of the 16 level optical Bloch equations for the case of CaF molecules. From three-dimensional Monte Carlo simulations we estimate the temperature and density of our MOT to be $40 \mu K$ and $4 \times 10^8 cm^{-3}$ respectively for a molecule number of $10^5$.