基于腔内原位探测的空间冷原子微波钟

原子钟作为目前最精密的计时仪器,在国民经济和国家安全各领域发挥着重要作用。 在地球轨道卫星上运行高精度原子钟,可以在地球大范围内开展高精度时间同步与比对。 不同于以往通过抛射冷原子团两次经过微波腔实现 Ramsey 微波作用的空间冷原子钟,提出了一种新型的基于腔内原位探测的空间冷原子微波钟方案,在同一微波谐振腔内先后完成铷 87 原子的激光冷却、原子微波相互作用、冷原子探测等过程。 该方案可以更好的利用微重力环境提高钟周期中原子与微波相互作用时间的占空比,从而有效减小 Dick 效应对原子钟性能的影响。 介绍了冷原子微波钟系统设计与工作原理,给出了微重力环境下性能分析和预期指标,最后展示了冷原子微波钟地面测试中获得的大约为 1. 35×10-12τ-1/ 2 的频率稳定度,初步展示了新型空间冷原子钟方案的可行性。

Space cold atoms microwave clock based on in-situ detection in the cavity

The atomic clock, as the most precise timing instrument at present, is playing an important role in various fields of nationaleconomy and security. By operating atomic clocks on earth orbit satellites, many high-precision time synchronization and comparison-related applications can be implemented on a large scale on the earth. Unlike previous space cold atomic clocks that achieve microwaveand atoms interaction by launching cold atoms cloud to traveling two microwave cavities, this article proposes a new space cold atomicmicrowave clock scheme based on in situ detection in the cavity. This scheme completes the laser cooling of rubidium 87 atoms, atomsand microwave interaction, cold atom detection, and other clock processes in the same microwave resonant cavity. It is possible to morefully utilize the microgravity environment to increase the duty cycle of the interaction time between atoms and microwaves in the clockcycle. Therefore, the impact of the Dick effect on the performance of atomic clocks is reduced. This article introduces the design andworking principle of this kind of cold atoms microwave clock system, provides performance analysis and expected frequency stability in amicrogravity environment, and finally shows that in the ground test results of the clock prototype. The tested 1. 35×10-12τ-1/ 2frequencystability of the cold atom microwave clock demonstrates the potential performance of the clock operating in microgravity environments.