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Sub-Doppler laser cooling of $^{39}$K via the 4S$\to$5P transition

by Govind Unnikrishnan, Michael Gröbner, Hanns-Christoph Nägerl

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Submission summary

Authors (as registered SciPost users): Govind Unnikrishnan
Submission information
Preprint Link:  (pdf)
Date accepted: 2019-03-29
Date submitted: 2019-03-26 01:00
Submitted by: Unnikrishnan, Govind
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
  • Atomic, Molecular and Optical Physics - Experiment
  • Quantum Physics
Approach: Experimental


We demonstrate sub-Doppler laser cooling of $ ^{39} $K using degenerate Raman sideband cooling via the 4S$_{1/2} \rightarrow $5P$ _{1/2} $ transition at 404.8 nm. By using an optical lattice in combination with a magnetic field and optical pumping beams, we obtain a spin-polarized sample of up to $5.6 \times 10^{7}$ atoms cooled down to a sub-Doppler temperature of 4 $\mu $K, reaching a peak density of $3.9 \times 10^{9}$ atoms/cm$ ^{3} $, a phase-space density greater than $ 10^{-5} $, and an average vibrational level of $ \langle \nu \rangle=0.6 $ in the lattice. This work opens up the possibility of implementing a single-site imaging scheme in a far-detuned optical lattice utilizing shorter wavelength transitions in alkali atoms, thus allowing improved spatial resolution.

Author comments upon resubmission

We thank the referees for their comments. We have made all three changes recommended in Report 2.

List of changes

Please see reply to Response 2.

Published as SciPost Phys. 6, 047 (2019)

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