Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

Abstract

We report precision measurements of the excited state lifetime of the $5p$ $^{2}P_{1∕2}$ and $5p$ $^{2}P_{3∕2}$ levels of a single trapped ${\mathrm{Cd}}^{+}$ ion. Combining ion trap and ultrafast laser technologies, the ion is excited with picosecond laser pulses from a mode-locked laser and the distribution of arrival times of spontaneously emitted photons is recorded. The resulting lifetimes are $3.148\ifmmode\pm\else\textpm\fi{}0.011\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ and $2.647\ifmmode\pm\else\textpm\fi{}0.010\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ for $^{2}P_{1∕2}$ and $^{2}P_{3∕2}$ respectively. With a total uncertainty of under 0.4%, these are among the most precise measurements of any atomic state lifetimes to date.