Preparation, Cooling, and Spectroscopy of Single, Localized Ions

Abstract

Certainly the most desirable conditions of experiments, to which an atomic physicist could ever aspire under the viewpoint of clarity and simplicity, include the preparation of a single, well-localized atomic particle. The realization of this concept, which requires some kind of entropy reduction or “cooling” of the particle [1, 2], would dramatically simplify the interpretation of experiments, e.g. in quantum statistics, and in studies of collective interactions with electromagnetic fields. Moreover, spectroscopic investigations of that particle could particularly benefit from the absence of most spectral broadening mechanimus: Doppler effect of 1st and 2nd order, transit-time broadening, and collisional broadening are eliminated [3]. Since only natural broadening is left over, this concept permits the detection of optical lines of unprecedented sharpness, and it offers an approach towards the ultimate atomic time and length standard.