Smoothing a current-carrying atomic mirror

We have measured the magnitude and roughness of the reflecting potential pr oduced by a current-carrying magnetic mirror from which cold rubidium atoms have been bounced at normal incidence. By varying the current in the mirro r, a study of the potential barrier from which the atoms in different magne tic substates bounce has been made. A combination of time-of-flight and ima ging techniques allowed us to study the roughness of the reflecting potenti al. We have demonstrated that the observed roughness can be reduced by addi tional wires to compensate for the finite-size effects, and by careful cont rol of the direction of the magnetic bias field.