We directly measure the branching ratio of the $5s4d{}^1{D}_2\to 5s5p{}^3{P}_2$ transition and the decay rate of the $5s5p{}^1{P}_1\to 5s4d{}^1{D}_2$ transition in neutral strontium. For more than four decades, these quantities lacked an experimental determination independent of theoretical input. We measure the branching ratio to be 0.177(4), significantly lower than the widely cited theoretical value of 0.322 [C. W. Bauschlicher, Jr. et al., J. Phys. B: At. Mol. Phys. 18, 1523 (1985)]. We also determine the decay rate to be $5.3\left(5\right)\times {10}^3{\mathrm{s}}^{-1}$, consistent with the value reported by Hunter et al. [Phys. Rev. Lett. 56, 823 (1986)] but substantially lower than the recent theoretical prediction of $9.25\left(40\right)\times {10}^3{\mathrm{s}}^{-1}$ [A. Cooper et al., Phys. Rev. X 8, 041055 (2018)]. These measurements provide an experimental benchmark for quantitative modeling of loss processes in laser cooling and single-atom fluorescence detection in optical tweezers with Sr.

Close

PrevNext

View figure in article

• Cooling & trapping