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arXiv · 1305.5480

Quantum interference-enhanced deep sub-Doppler cooling of 39 K atoms in gray molasses

Dipankar Nath·R Kollengode Easwaran·G. Rajalakshmi·C. S. Unnikrishnan
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Abstract

We report enhanced sub-Doppler cooling of the bosonic atoms of $^{39}$K facilitated by formation of dark states tuned for the Raman resonance in the $Λ-$configuration near the D1 transition. Temperature of about 12 $μ$K is achieved in the two stage D2-D1 molasses and spans a very large parameter region where quantum interference persists robustly. We also present results on enhanced radiation heating with sub-natural linewidth (0.07$Γ$) and signature Fano like profile of a coherently driven 3-level atomic system. The Optical Bloch Equations relevant for the three-level atom in bichromatic light field is solved with the method of continued fractions to show that cooling occurs only for a small velocity class of atoms, emphasizing the need for pre-cooling in D2 molasses stage.

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Dipankar Nath, R Kollengode Easwaran, G. Rajalakshmi, C. S. Unnikrishnan. 2013-09-04. Quantum interference-enhanced deep sub-Doppler cooling of 39 K atoms in gray molasses. https://doi.org/10.1103/physreva.88.053407

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