ABSTRACT
The concept of radiation-pressure cooling of atoms was independently suggested in 1975 for the case of a gas of neutral atoms by Hansch and Schawlow, and for atomic ions bound in an electromagnetic trap by Wineland and Dehmelt. While the notion that momentum exchange from a photon moving in the opposite direction could slow an individual atom was well understood, until this time no one had come up with a means for producing an aggregate cooling of a larger ensemble of atoms (a gas). The general feature of the cooling concepts is that a gas of atoms or ions can be cooled by ensuring that photon absorption takes place preferentially when the atoms or ions are moving against the flow of photons from a laser. A unique aspect of the ion-cooling work has been the ability to do experiments with individual atoms.
