Sub-Doppler laser cooling of potassium atoms

Authors :: Landini, M.
Roy, S.
Carcagni', L.
Trypogeorgos, D.
Fattori, M.
Inguscio, M.
Modugno, G.
Source :: Phys. Rev. A 84, 043432 (2011)
Publication Year :: 2011
Abstract: We investigate sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of systems and an adiabatic ramping of the laser parameters allows to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25(3)microK and 47(5)microK in high-density samples of the two isotopes 39K and 41K, respectively. Our findings will find application to other atomic systems.<br />Comment: 7 pages, 9 figures