Abstract

Singly ionized mercury ions have been stored in a miniature rf (Paul) quadruple ion trap and observed by means of resonance fluorescence. The trap electrode spacings (~0.5 mm) and rf voltage (~500 V at 20 MHz) were chosen¹ so that the Lamb-Dicke criterion could be satisfied for optical transitions on a single-laser-cooled ion. The presence of a single ion was determined by a statistical loading method²; that is, the loading conditions were scaled down to a point where only occasionally would any fluorescence be observed after a loading cycle. With high probability, this fluorescence was due to a single ion. The fluorescence observed was due to spontaneous scattering from a 194-nm cw source (~3-μW power focused to a beam waist of ~20 μm) directed at the ion and tuned near the strongly allowed first resonance line.

© 1986 Optical Society of America