$\Lambda$-enhanced sub-Doppler cooling in a grating magneto-optical trap

ORAL

Abstract

We report our observation of sub-Doppler cooling of lithium using a tetrahedral laser beam arrangement, which is produced by a nanofabricated diffraction grating. We are able to capture $10~\%$ of the lithium atoms from a grating magneto-optical trap into $\Lambda$-enhanced $D_1$ gray molasses. The molasses cools the captured atoms to approximately $30~\mu$K. In contrast to results from conventional counterpropagating beam configurations, we do not observe cooling when our optical fields are detuned from Raman resonance. Our results show that grating magneto-optical traps can serve as a robust source of cold atoms for tweezer-array and atom-chip experiments, even when the atomic species is not amenable to sub-Doppler cooling in bright optical molasses.

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Authors

  • Daniel S. Barker

    • Joint Quantum Institute
    • Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742

  • Eric B. Norrgard

    • Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology, College Park, MD 20742

  • Nikolai N. Klimov

    • Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899

  • Stephen Eckel

    • Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899