Laser cooling below a photon recoil with three-level atoms

Abstract

We demonstrate a new cooling technique which is used to cool sodium atoms in one dimension to an effective temperature of 100 nK, less than 1/10 of the single photon recoil temperature ${\mathit{k}}_{\mathit{B}}$ ${\mathit{T}}_{\mathrm{rec}}$=(ħk${)}^2$/2M.