Imaging a $^6$Li Atom In An Optical Tweezer 2000 Times with $\Lambda$-Enhanced Gray Molasses

TL;DR

This paper demonstrates high-fidelity imaging of lithium-6 atoms in an optical tweezer using $ Lambda$-enhanced gray molasses, achieving a record low-loss rate and enabling advanced quantum state preparation.

Contribution

It introduces a novel imaging technique with unprecedented survival rate for lithium-6 atoms and a new cooling model for optical tweezer applications.

Findings

Imaging survival of 0.99950(2) for lithium-6 in optical tweezers.

Enhanced loading rate of 0.7 from MOT to tweezer.

Cooling to 70 μK with a new predictive cooling model.

Abstract

We have imaged lithium-6 thousands of times in an optical tweezer using $\Lambda$-enhanced gray molasses cooling light. Despite being the lightest alkali, with a recoil temperature of 3.5 $\mu$K, we achieve an imaging survival of 0.99950(2), which sets the new benchmark for low-loss imaging of neutral atoms in optical tweezers. Lithium is loaded directly from a MOT into a tweezer with an enhanced loading rate of 0.7. We cool the atom to 70 $\mu$K and present a new cooling model that accurately predicts steady-state temperature and scattering rate in the tweezer. These results pave the way for ground state preparation of lithium en route to the assembly of the LiCs molecule in its ground state.