A Single Laser Cooled Trapped ⁴⁰Ca⁺ Ion in a Miniature Paul Trap

We have observed the phenomenon of phase transition of a few trapped ions in a miniature Paul trap. Judging from the quantum jump signals, a single laser-cooled trapped Ca⁺ ion has been realized. The ion temperature is estimated to be 22mK. The result shows that the amplitude of ion micromotion is strongly dependent on the rf voltage.