Laser Cooling of 85Rb Atoms to the Recoil Temperature Limit

TL;DR

This paper reports the successful laser cooling of 85Rb atoms to the recoil temperature limit using a two-dimensional optical lattice and a degenerate Raman sideband cooling scheme, achieving rapid cooling within 2.4 ms.

Contribution

It demonstrates a novel application of degenerate Raman sideband cooling in a 2D optical lattice to reach the recoil temperature for 85Rb atoms.

Findings

Atoms cooled to recoil temperature in 2.4 ms

Cooling method allows independent control of heating and cooling rates

Achieved cooling in both dimensions within a short timescale

Abstract

We demonstrate the laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], 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 eta=0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimension within 2.4 ms with the aid of adiabatic cooling.