Fast optical transport of ultracold molecules over long distances

TL;DR

This paper demonstrates a rapid optical transport method for ultracold CaF molecules over long distances using an optical lattice and focus-tunable lens, enabling improved placement and stability for quantum experiments.

Contribution

It introduces a novel fast transport technique for ultracold molecules combining an electronically focus-tunable lens with an optical lattice, achieving high efficiency and stability.

Findings

Transported CaF molecules over 46 cm in 50 ms with 48% efficiency.

Transported molecules experienced moderate heating from 32 μK to 53 μK.

Stable loading of single molecules into optical tweezer arrays was demonstrated.

Abstract

Optically trapped laser-cooled polar molecules hold promise for new science and technology in quantum information and quantum simulation. Large numerical aperture optical access and long trap lifetimes are needed for many studies, but these requirements are challenging to achieve in a magneto-optical trap (MOT) vacuum chamber that is connected to a cryogenic buffer gas beam source, as is the case for all molecule laser cooling experiments so far. Long distance transport of molecules greatly eases fulfilling these requirements as molecules are placed into a region separate from the MOT chamber. We realize a fast transport method for ultracold molecules based on an electronically focus-tunable lens combined with an optical lattice. The high transport speed is achieved by the 1D red-detuned optical lattice, which is generated by interference of a focus-tunable laser beam and a focus-fixed laser beam. Efficiency of 48(8)% is realized in the transport of ultracold calcium monofluoride (CaF) molecules over 46 cm distance in 50 ms, with a moderate heating from 32(2) {\mu}K to 53(4) {\mu}K. Positional stability of the molecular cloud allows for stable loading of an optical tweezer array with single molecules.