POLARIZATION GRADIENT COOLING OF TRAPPED IONS

We report the first experimental demonstration of one-dimensional pola rization gradient cooling of bound ions. The trapped particles are onl y weakly bound along the laser cooling axis. Nevertheless, the particl e motion has to be treated quantum mechanically. The minimum kinetic e nergy is found when the depth of the optical potential approaches a qu antum of the vibrational energy of the trapped ions. Cooling to low vi brational states of the trap has been observed. We have also produced the lowest one-dimensional temperature for an ion crystal.