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

Tobias Bothwell; Junxin Chen; Brian M. Fields; Madeline K. Dawes; Anthony Reiter; Christina C. C. Willis; Jacob Scott; Michael McMaster; Farhad Majdeteimouri; Ilya Vinogradov; Seth Miers; Daniel C. Cole; Kevin Loeffler; Ryan A. Jones; Marin Iliev; Jonathan Gilbert; Eric Copenhaver; Thomas W. Noel; Alexander G. Radnaev

arXiv · 2604.08876

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

Tobias Bothwell·Junxin Chen·Brian M. Fields·Madeline K. Dawes·Anthony Reiter·Christina C. C. Willis·Jacob Scott·Michael McMaster·Farhad Majdeteimouri·Ilya Vinogradov·Seth Miers·Daniel C. Cole·Kevin Loeffler·Ryan A. Jones·Marin Iliev·Jonathan Gilbert·Eric Copenhaver·Thomas W. Noel·Alexander G. Radnaev

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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.

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Tobias Bothwell, Junxin Chen, Brian M. Fields, Madeline K. Dawes, Anthony Reiter, Christina C. C. Willis, Jacob Scott, Michael McMaster, Farhad Majdeteimouri, Ilya Vinogradov, Seth Miers, Daniel C. Cole, Kevin Loeffler, Ryan A. Jones, Marin Iliev, Jonathan Gilbert, Eric Copenhaver, Thomas W. Noel, Alexander G. Radnaev. 2026-04-10. Sub-Doppler laser cooling and optical transport of cesium with static magnetic fields. https://arxiv.org/abs/2604.08876

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