Sub-Doppler cooling of sodium atoms in Gray Molasses
Abstract
Sub-Doppler Cooling is widely employed, however in applications of high atomic density or when the energy spectrum is not well resolved its performances are degraded. A solution to those limitation was recently demonstrated both on lithium and on potassium atoms by laser cooling on the D1 optical transition where the levels are better resolved and where Dark States can be realized in a Raman configuration, removing the constraints on the spatial density by reducing the scattering rate and, at the same time, to reducing the temperature thanks to the Raman coupling configuration. We apply the this cooling method to sodium atoms and observe performances similar to those already reported for Li and K.