Sub-Doppler laser cooling and optical transport of cesium with static magnetic fields

TL;DR

This paper demonstrates sub-Doppler laser cooling and optical transport of cesium atoms using a static magnetic field setup, enabling continuous cooling and transport without dynamic magnetic fields.

Contribution

It introduces a static magnetic-field configuration for sub-Doppler cooling and transport of alkali atoms, avoiding the need for time-varying magnetic fields.

Findings

Achieved 17 μK temperatures in cesium without changing magnetic-field gradients.

Enabled direct loading into a shallow optical lattice from a static magnetic environment.

Demonstrated transport of atoms over 17 cm within a static-field platform.

Abstract

Laser cooling of alkali atoms typically requires time-varying magnetic fields, introducing unwanted coupling between atom preparation and coherent operations. Here we demonstrate sub-Doppler laser cooling and optical transport of alkali atoms in a fully static magnetic-field configuration. Using a blue-detuned Type-II magneto-optical trap (MOT) operating on the closed $F=3 \rightarrow F'=2$ transition of the D2 line in cesium, we achieve temperatures of 17(1) $\mu$K without changing the magnetic-field gradient between cooling stages. This enables direct loading into a shallow optical lattice and transport over 17 cm within the same static-field environment. In contrast to conventional alkali cooling schemes with dynamic fields, our approach establishes a continuous cooling and transport protocol compatible with static-field platforms. These results validate Type-II cooling as a practical technique for alkali atoms and provide a new route toward continuous-operation architectures in sensing and quantum computing.