A Single Laser Cooled Trapped ^40Ca^＋ Ion in a Miniature Paul Trap

We have observed the phenomenon of phase transition of a few trapped ions in a miniature Paul trap. Judging from the quantum jump signa/s, a single laser-cooled trapped Ca^ ion has been realized. The ion temperature is estimated to be 22 mK. The result shows that the amplitude of ion micromotion is strongly dependent on the rf voltage.     

Laboratory demonstration of geopotential measurement using transportable optical clocks

We report an experimental demonstration of geopotential difference measurement using a pair of transportable $^{40}$Ca$^{+}$ optical clocks (TOC-729-1 and TOC-729-3) in the laboratory, each of them has an uncertainty of $1.3 \times 10^{-17}$ and an instability of $4.8 \times 10^{-15}/\sqrt{ \tau } $. Referenced to a stationary clock of TOC-729-1, the geopotential difference measurements are realized by moving TOC-729-3 to three different locations and the relevant altitude differences are measured with uncertainties at the level of 20 cm. After correcting the systematic shifts (including gravitational red shift), the two-clock frequency difference is measured to be $-0.7(2.2) \times 10^{-17}$, considering both the statistic $(1.0 \times 10^{-17})$ and the systematic $(1.9 \times 10^{-17})$ uncertainties. The frequency difference between these two clocks is within their respective uncertainties, verifying the reliability of transportable $^{40}$Ca$^{+}$ optical clocks at the low level of 10$^{-17}$.     

Paul阱中基态低能多离化Fen+(n=1-3)离子的存储及反应特性

利用垂直交叉的激光束在Paul阱中溅射固体铸铁(FeC)靶,产生了低能多电荷铁离子Fen+(n=1-3),得到了Fe3+离子在本底气压为3.0×10-7Pa下的衰减速率(0.96s-1)以及在1.3×10-5Pa下和中性气体分子N2的反应产物.     

Paul阱中基态低能多离化Fen+(n=1—3)离子的存储及反应特性

利用垂直交叉的激光束在Paul阱中溅射固体铸铁（FeC）靶，产生了低能多电荷铁离子 Feⁿ⁺(n=1—3), 得到了Fe³⁺离子在本底气压为3.0×10^-7 Pa下的衰减速率（0.96 s^-1）以及在1.3×10^-5 Pa下和中性气体分子N₂的反应产物. 关键词： Paul阱 低能多离化离子 反应特性     

Experimental Improvement of Signal of a Single Laser-Cooled Trapped ^40Ca^＋ Ion

A single ^40Ca^＋ ion is loaded in a miniature Paul trap and the probability of directly loading a single ion is above 50%. The signal-to-noise ratio and the storage time for a single ion have been improved by minimizing the ion micromotion and locking a 397nm cooling laser to a Fabry-Perot interferometer and optogalvanic signal. From the fluorescence spectrum, the ion temperature is estimated to be about 5mK.