Local dynamics of laser cooling in an optical lattice

Abstract

Using the basis of Wannier states, we study the local dynamics of polarization gradient cooling for an atom driven on a ${J}_{g}=2\ensuremath{\rightarrow}{J}_{e}=3$ transition by a one-dimensional optical lattice. This analysis allows us to formulate a physical picture of the cooling mechanism, analogous to Sisyphus cooling for a ${J}_{g}=1/2\ensuremath{\rightarrow}{J}_{e}=3/2$ atom, which depends strongly on coherences in the Zeeman sublevels of the ground state. In addition, we are able to explain the steady-state properties of the laser-cooled atoms in a regime where the standard semiclassical analysis breaks down.