Abstract: The authors report on the current status of the optical frequency standard based on a single ¹¹⁵In⁺ ion. A single Indium ion is trapped in a Paul-Straubel type trap and cooled by sideband cooling to its lowest vibrational states. To interrogate the 5s²¹S₀-5s5p³P₀ clock transition with high accuracy, the authors demonstrate a Hz-level level laser system resonant to this transition. The Absolute frequency measurement is performed with the help of a femtosecond laser referenced to a commercial cesium atomic clock. 20 sessions measurements are achieved. The relative fractional uncertainty is 5.0×10^-14.

Key words: single ion, absolute frequency measurement, femtosecond laser

摘要： 报道了建立铟单离子(¹¹⁵In⁺)光频标实验系统的实验进展。单个离子囚禁在Paul-Straubel型离子阱中，利用激光边带冷却技术将其冷却至最低振动能态。为了探测和测量铟离子参考用跃迁5s²¹S₀-5s5p³P₀的频率，使用一台Hz量级超窄线宽激光作为探测激光，用以获得量子跳跃信号。用一台以商用铯原子钟为基准的飞秒光频梳作为测量工具，对其频率进行了20次的精密测量，相对不确定度为5.0×10^-14。

关键词: 单离子, 绝对频率测量, 飞秒光频梳