Sub-Doppler Laser Cooling of²³Na in Gray Molasses on theD₂Line

Abstract

We report on the efficient gray molasses cooling of sodium atoms using the D2 optical transition at 589.1 nm. Thanks to the hyperfine split about between and in the excited state , this atomic transition is effective for the gray molasses cooling mechanism. Using this cooling technique, the atomic sample in F = 2 ground manifold is cooled from to in 3.5 ms. We observe that the loading efficiency into magnetic trap is increased due to the lower temperature and high phase space density of atomic cloud after gray molasses. This technique offers a promising route for the fast cooling of the sodium atoms in the F = 2 state.

Production of dual species Bose–Einstein condensates of 39K and 87Rb*

“…Then a resonant flash light of 1 ms length removes the residual 87 Rb atoms in the |2, 2 state. After another 1 ms of wait, the 39 K atoms are also transferred adiabatically to the |F = 1, m F = 1 state using an RF sweep in 100 ms and a similar flash light follows removing the remaining 39 K atoms in the |2, 2 state. The transfer efficiency is almost 95 percent.…”

“…Dual species ultracold gasses greatly expand the research area of this platform to study even more complex physical phenomena that are not accessible in a single component quantum gas, such as producing heteronuclear molecules with long dipole-dipole interaction [15][16][17], creating polarons near quantum criticality [18][19][20] and observation of collective dynamics of a mixture of Bose and Fermi superfluids [21]. To date, several dual Bose-Bose species have been cooled to BECs in experiments, including 23 Na-87 Rb [22], 39 K-87 Rb [23], 39 K- 23 Na [24], 41 K-87 Rb [25,26], 88 Sr-87 Rb, 84 Sr-87 Rb [27], Er-Dy [28], and 133 Cs-87 Rb [29,30].…”

“…Third, the strong light-assisted losses of the dual species in the initial double MOTs stage [34] result in a poor loading. All of these factors make the achievement of 39 K-87 Rb dual-species BECs to be a challenging task.…”

“…The experimental setup for the dual39 K and 87 Rb BECs showing the two MOT cells and the ion pumps for each chamber. The Rb and K sources (at 40 and 45 0 C respectively) supply atoms into the 2D MOT chamber.…”

“…FIG.5:The Feshbach resonance spectrum for the mixture39 K and 87 Rb in the |1, 1 states. The upper panel shows the number of atoms remaining in the trap for39 K and the lower panel shows that for 87 Rb.…”