Golovizin Artem A, Tregubov Dmitry O, Fedorova Elena S, Mishin Denis A, Provorchenko Daniil I, Khabarova Ksenia Yu, Sorokin Vadim N, Kolachevsky Nikolai N
P.N. Lebedev Physical Institute, Moscow, Russia.
Russian Quantum Center, Moscow, Russia.
Nat Commun. 2021 Aug 27;12(1):5171. doi: 10.1038/s41467-021-25396-8.
Optical atomic clocks have already overcome the eighteenth decimal digit of instability and uncertainty, demonstrating incredible control over external perturbations of the clock transition frequency. At the same time, there is an increasing demand for atomic (ionic) transitions and new interrogation and readout protocols providing minimal sensitivity to external fields and possessing practical operational wavelengths. One of the goals is to simplify the clock operation while maintaining the relative uncertainty at a low 10 level achieved at the shortest averaging time. This is especially important for transportable and envisioned space-based optical clocks. Here, we demonstrate implementation of a synthetic frequency approach for a thulium optical clock with simultaneous optical interrogation of two clock transitions. Our experiment shows suppression of the quadratic Zeeman shift by at least three orders of magnitude. The effect of the tensor lattice Stark shift in thulium can also be reduced to below 10 in fractional frequency units. This makes the thulium optical clock almost free from hard-to-control systematic shifts. The "simultaneous" protocol demonstrates very low sensitivity to the cross-talks between individual clock transitions during interrogation and readout.
光原子钟已经克服了不稳定性和不确定性的第十八个十进制数位，展示了对时钟跃迁频率外部扰动的惊人控制能力。与此同时，对原子（离子）跃迁以及新的询问和读出协议的需求日益增加，这些协议对外场的敏感度最低且具有实用的工作波长。目标之一是简化时钟操作，同时在最短平均时间内将相对不确定性维持在低至10的水平。这对于可运输的以及设想中的天基光钟尤为重要。在此，我们展示了一种用于铥光钟的合成频率方法的实现，同时对两个时钟跃迁进行光学询问。我们的实验表明二次塞曼频移被抑制了至少三个数量级。铥中张量晶格斯塔克频移的影响在分数频率单位中也能降低到10以下。这使得铥光钟几乎不受难以控制的系统频移影响。“同时”协议在询问和读出过程中对各个时钟跃迁之间的串扰表现出极低的敏感度。
