Abstract
The paper reports experimental investigations on 171Yb ions confined in a radiofrequency Paul trap. Single ions are cooled and optically detected by laser excitation of the cycling F = 1 – F = 0 hyperfine component of the 2S1/2 – 2P1/2 resonance transition. The metastable 2D3/2(F = 1) level which is rapidly populated by decay from the 2P1/2 level is depleted by a second laser source. The resonance fluorescence signal exhibits dark periods due to a small rate of spontaneous transitions to the 2D3/2(F = 2) level which is coupled only weakly to the laser-cooling excitation cycle. Prospects for an optical frequency standard based on excitation of the narrow 2S1/2(F = 0) – 2D3/2(F = 2) transition of 171Yb+ at a wavelength of 435 nm are discussed.