Coherent excitation of normal modes in a string of Ca^+ ions

Abstract
Crystal structures of Calcium ions have been prepared in a linear Paul trap and their collective motion excited with resonant rf-fields. The trapped ions are laser-cooled and images of the fluorescing ions are obtained with a CCD camera and show high spatial resolution. Crystals with up to 15 ions arrange in a linear string and their eigenmodes can subsequently be selectively excited. The collective motion of the string can then be observed via the CCD images.