基于AOM的CPT原子钟差分降噪实验研究

Noise Cancellation by an Acousto-Optic Modulator in CPT Atomic Clocks

本文提出了一种降低相干布居囚禁CPT(coherent population trapping)原子钟噪声,提高短期稳定度的方法。在我们的实验装置中,经过AOM而产生的两束光通过同一个原子气室。一束圆偏振光用于产生CPT,另一束线偏振光只发生共振吸收,两者差分就可以消除共模噪声。通过AOM射频开关的打开和关闭,可以完成传统CPT原子钟和差分检测方案之间的转换,便于进行对照实验。实验结果表明,差分检测方案将原子钟的百秒稳定度提高了1.4倍。

An approach is presented to suppress noise and improve short-term stability in CPT atomic clocks.In our setup,two divided beams from AOM(acousto-optic modulator)were sent through a same alkali vapor cell.One beam induced CPT by circularly polarized light and another beam induced only absorption by linearly polarized light.Differential algorithm counteracts common-mode noise by subtraction.Also,it is contrastive to switch between traditional CPT detection and differential detection by simply switching AOM radio frequency input off or on.As a result,the noise cancellation scheme improves the short-term stability of the clock by a factor of 1.4 at the second of 100s.