The natural lifetime of the metastable $4d{}^{2}D_{5∕2}$ state in ${}^{88}\mathrm{Sr}^{+}$ has been measured using a single laser-cooled, trapped ion. The ion was prepared in the $4d{}^{2}D_{5∕2}$ state by laser excitation of the $5s{}^{2}S_{1∕2}-4d{}^{2}D_{5∕2}$ quadrupole transition at 674 nm. The decay time was measured by using Dehmelt’s electron shelving method to monitor the ion’s electronic state. Two separate investigations were conducted under slightly different experimental conditions. 160 000 decay times from the $4d{}^{2}D_{5∕2}$ state were observed in total, and two different methods for determining the statistical value of the measured lifetime have been compared. Systematic effects have also been estimated, and including these effects yields a value of $\tau =390.8\left(1.6\right)\mathrm{ms}$ ($1\sigma$ uncertainty) for the natural lifetime.

• Received 8 February 2005

DOI:https://doi.org/10.1103/PhysRevA.72.012509