We report a measurement of the lifetime of the 3d 2D_{5/2} metastable level in 40Ca+, using quantum jumps of a single cold calcium ion in a linear Paul trap. The 4s S_{1/2} - 3d D_{5/2} transition is significant for single-ion optical frequency standards, astrophysical references, and tests of atomic structure calculations. We obtain tau = 1.168 +- 0.007 s from observation of nearly 64,000 quantum jumps during approximately 32 hours. Our result is more precise and significantly larger than previous measurements. Experiments carried out to quantity systematic effects included a study of a previously unremarked source of systematic error, namely excitation by the broad background of radiation emitted by a semiconductor diode laser. Combining our result with atomic structure calculations yields 1.20 +- 0.01 s for the lifetime of 3d D_{3/2}. We also use quantum jump observations to demonstrate photon anti-bunching, and to estimate background pressure and heating rates in the ion trap.
Precision lifetime measurement of the cesium $6P_{3/2}$ level using ultrafast pump-probe laser pulses
利用锁模激光脉冲固有的定时稳定性，我们精确地测量了铯原子$6P_{3/2}$的激发态寿命。初始泵浦脉冲将两束反向传播原子束中的铯原子激发到$6P_{3/2}$能级。随后的同步探测脉冲电离保持在激发态的原子，并且收集和计数光离子。通过选择相对于探测脉冲随时间变化的泵浦脉冲，我们获得了随时间变化的激发态布居的采样，得到30.462（46）ns的寿命值。由于纳入了额外数据和系统误差，测量不确定度（0.15%）大于我们之前报告的0.12% [Phys. Rev. A 84，010501（R）（2011）]。在这个后续文件中，我们提出的主要系统误差在测量中遇到的细节，其中包括原子运动的激光束的强度分布，量子拍频的光离子信号，和辐射捕获。文中还讨论了进一步降低实验不确定度的改进措施
New experimental and theoretical approach to the 3d D-level lifetimes of 40Ca+
本文报道了在线性Paul阱中激光冷却$^{40}$ Ca $^+$离子的3d $^2$ D $_{5/2}$和3d $^2$ D $_{3/2}$亚稳态寿命的测量结果。我们介绍了一种新的测量技术的基础上高效率的量子态检测后的相干激发的D $_{5/2}$状态或非相干搁置在D $_{3/2}$状态，随后的自由，无扰自发衰变。D $_{5/2}$态的自然寿命为1168（9）ms，这一结果与最精确的公布值非常吻合。D $_{3/2}$态的寿命首次用单离子测量，得到1176（11）ms，这将以前结果的统计不确定性提高了四倍。我们将这些实验寿命与高精度从头算全阶计算进行了比较，并找到了非常好的一致性。这些计算代表了高精度原子理论的一个很好的测试，并将作为一个基准的宇称不守恒的研究在Ba $^+$具有相似的原子结构。
