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arXiv:1807.05745 · Physical Review A

Λ -enhanced gray-molasses cooling of cesium atoms on the D2 line

Ya-Fen Hsiao, Y.-J. Lin, Ying-Cheng Chen

Published Sep 28, 2018• 20 citations
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Abstract

We present a systematic study of the $\mathrm{\ensuremath{\Lambda}}$-enhanced gray molasses cooling ($\mathrm{\ensuremath{\Lambda}}$-GMC) of cesium atoms on the ${D}_{2}$ transition. Due to the large splitting in the excited hyperfine transitions of the cesium ${D}_{2}$ line, it is relatively simple to implement the $\mathrm{\ensuremath{\Lambda}}$-GMC with a suitable frequency control of the trapping and repumping lasers of the magneto-optical trap (MOT). We achieve a temperature of $1.7\ifmmode\pm\else\textpm\fi{}0.2\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{K}$ with $3.2\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms. The phase space density of atoms is $1.43\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. Compared to the condition with a bare MOT or a MOT with gray-molasses cooling without $\mathrm{\ensuremath{\Lambda}}$ enhancement, there is an increase in the phase space density by a factor of more than ${10}^{3}$ and 10, respectively.

DOI
10.1103/physreva.98.033419

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ΛΛΛ-Enhanced Gray Molasses Cooling of 85^{85}85Rb Atoms in Tweezers Using the D2_22​ Line
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Sub-Doppler laser cooling of40K with Raman gray molasses on the D2{D}_{2}D2​ line
Gray molasses is a powerful tool for sub-Doppler laser cooling of atoms to low temperatures. For alkaline atoms, this technique is commonly implemented with cooling lasers which are blue-detuned from either the D 1 or D 2 line. Here we show that efficient gray molasses can be implemented on the D 2 line of 40 K with red -detuned lasers. We obtained temperatures of , which enables direct loading of atoms from a magneto-optical trap into an optical dipole trap. We support our findings by a one-dimensional model and three-dimensional numerical simulations of the optical Bloch equations which qualitatively reproduce the experimentally observed cooling effects.
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