Laser cooling of Rb 85 atoms to the recoil-temperature limit

We demonstrate the laser cooling of Rb85 atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman, Phys. Rev. Lett. 84, 439 (2000)PRLTAO0031-900710.1103/PhysRevLett.84.439], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter η=0.45 and show the cooling of spin-polarized Rb85 atoms to the recoil temperature in both dimensions within 2.4 ms with the aid of adiabatic cooling.