锁定参数与光钟稳定度关系的研究

Research on relationship between locking parameters and stability of optical clocks

从量子力学原理出发,结合光钟的锁定算法,分析了光钟输出频率噪声的产生机制;并以钙离子光钟为例,用蒙特卡洛方法在计算机上模拟了光钟运行,获得光钟的稳定度,且在同样参数下,与实验测得的稳定度进行了比较,结果表明两者具有较好的一致性。同时,通过修改光钟运行中的参数,研究了反馈周期内每个频率点探测离子次数N、增益系数g及激光的线性漂移对光钟稳定度的影响。结果表明光钟的秒稳对每个反馈周期内探测离子的次数N不敏感;且在g>0.45时,稳定度开始变差;此外,相对于钟激光的线性漂移,量子投影噪声对稳定度起主导作用。本研究提出的模拟光钟运行的方法能方便地应用到其他离子与原子光钟上,可对不同实验参数下光钟的稳定度进行评估。

Based on the principles of quantum mechanics and the locking algorithm of optical clocks,the generation mechanism of the optical clock output frequency noise is analyzed.Stabilities of single-ion optical clocks was derived from the results of Monte-Carlo simulations and compared with the experimental results.The times of the single ion interrogated by clock laser in each frequency feedback cycle N,and the gain coefficient g,were scanned respectively in simulation to studying the relationship between these parameters and the stabilities of optical clocks.Results show that the 1s stability of the optical clocks is insensitive to N and will degrade when g>0.45.In addition,compared to the quantum projection noise,stabilities caused by the clock laser's linear drift is negligible.The proposed simulation method of single-ion optical clocks can be easily achieved and applied to evaluate the stability of optical clocks with custom parameters.