We demonstrate a simple, general purpose method to cool neutral atoms. A sample containing $3\ifmmode\times\else\texttimes\fi{}{10}^{8}$ cesium atoms prepared in a magneto-optical trap is cooled and simultaneously spin polarized in 10 ms at a density of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{11}\mathrm{cm}{}^{\ensuremath{-}3}$ to a phase space density $n{\ensuremath{\lambda}}_{\mathrm{dB}}^{3}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1/500$, which is almost 3 orders of magnitude higher than attainable in free space with optical molasses. The technique is based on 3D degenerate Raman sideband cooling in optical lattices and remains efficient even at densities where the mean lattice site occupation is close to unity.We demonstrate a simple, general purpose method to cool neutral atoms. A sample containing $3\ifmmode\times\else\texttimes\fi{}{10}^{8}$ cesium atoms prepared in a magneto-optical trap is cooled and simultaneously spin polarized in 10 ms at a density of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{11}\mathrm{cm}{}^{\ensuremath{-}3}$ to a phase space density $n{\ensuremath{\lambda}}_{\mathrm{dB}}^{3}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1/500$, which is almost 3 orders of magnitude higher than attainable in free space with optical molasses. The technique is based on 3D degenerate Raman sideband cooling in optical lattices and remains efficient even at densities where the mean lattice site occupation is close to unity.

Physical Review LettersJan 17, 2000264 citations

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

Govind Unnikrishnan, Michael Gröbner, Hanns‐Christoph Nägerl

We demonstrate sub-Doppler laser cooling of ^{39} 39 K using degenerate Raman sideband cooling via the 4S _{1/2} \rightarrow 1 / 2 → 5P _{1/2} 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} 5.6 × 10 7 atoms cooled down to a sub-Doppler temperature of 4 \upmu μ K, reaching a peak density of 3.9 \times 10^{9} 3.9 × 10 9 atoms/cm ^{3} 3 , a phase-space density greater than 10^{-5} 10 − 5 , and an average vibrational level of \langle \nu \rangle=0.6 ⟨ ν ⟩ = 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.We demonstrate sub-Doppler laser cooling of ^{39} 39 K using degenerate Raman sideband cooling via the 4S _{1/2} \rightarrow 1 / 2 → 5P _{1/2} 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} 5.6 × 10 7 atoms cooled down to a sub-Doppler temperature of 4 \upmu μ K, reaching a peak density of 3.9 \times 10^{9} 3.9 × 10 9 atoms/cm ^{3} 3 , a phase-space density greater than 10^{-5} 10 − 5 , and an average vibrational level of \langle \nu \rangle=0.6 ⟨ ν ⟩ = 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.

arXiv:1811.02185SciPost PhysicsApr 18, 20196 citations

Optical pumping of alkali atoms

Raoul Gregory Vitale

Jan 1, 19710 citations

Subrecoil Cooling of Alkali Atoms: Proposals and Perspectives

Eugeny Korsunsky, Laurentius Windholz

Jan 1, 19950 citations

Λ-enhanced grey molasses on the D2 transition of Rubidium-87 atoms

Sara Rosi, A. Burchianti, Stefano Conclave +4 more

Abstract Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phase-space density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D1 transition nS1/2 → nP1/2. We show that, for 87Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that “quasi-dark state” cooling is efficient also on the D2 line, 5S1/2 → 5P3/2. We report temperatures as low as (4.0 ± 0.3) μK and an increase of almost an order of magnitude in the phase space density with respect to ordinary laser sub-Doppler cooling.Abstract Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phase-space density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D1 transition nS1/2 → nP1/2. We show that, for 87Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that “quasi-dark state” cooling is efficient also on the D2 line, 5S1/2 → 5P3/2. We report temperatures as low as (4.0 ± 0.3) μK and an increase of almost an order of magnitude in the phase space density with respect to ordinary laser sub-Doppler cooling.

arXiv:1709.06467Scientific ReportsJan 16, 201862 citations

Sub-Doppler laser cooling of

^{39}

K via the 4S$\to$5P transition