铷原子的积分球冷却和磁囚禁关键技术研究

Compact cold atomic clocks for on-board systems have been one of the hot topics at the forefront of atomic clock research, and atomic clock based on integrating sphere cooling becomes one of the better candidates for the future generations. Therefore, the investigation of physical mechanisms and novel experimental techniques related to this issue is of great scientific and practical importance. The project aims to study and understand complex cooling mechanisms for rubidium atoms in diffused light field, and then build a magnetic trapping system to confine atoms . Novel experimental methods will be developed to suppress a variety of decoherence effects, which are beneficial to obtain a cold atom sample with long coherent time. We also are developing a novel detection technique of the magnetic-field-insensitive clock transition with polarization interference to obtain the Ramsey fringes with higher signal to noise ratio and improve the performance of integrating sphere atomic clocks. This project will have wide applications in various research fields, such as atomic frequency standards, quantum coherent control and precision measurement. It lays the foundation for developing a magnetic-field-insensitive transition of integrating sphere atomic clock, and particularly provides a novel technique to stimulate the development of national navigation and positioning technology.

小型化星载冷原子钟已成为当前原子钟研究的前沿课题之一，而基于积分球的原子钟是将来新一代星载原子钟中较好的候选者之一。因此，对积分球原子钟的相关物理机制和新的实验技术做深入探索有重要的科学意义和应用价值。本项目着力于研究和理解漫反射激光场中铷原子的复杂冷却机制，研制能长时间囚禁冷铷原子的磁阱系统，并通过抑制各种退相干效应的实验技术，获得有较长相干时间的冷原子团；发展磁不敏钟跃迁的偏振干涉探测新技术，争取获得高信噪比的Ramsey干涉条纹，进一步提高积分球冷原子钟性能。该项研究也将在原子频标、量子相干操控和精密测量等领域有广泛的应用前景。本项目的研究成果将为最终研制成磁不敏跃迁积分球冷原子钟奠定基础，有望为我国的导航定位系统提供一种新的星载原子钟技术，期待进一步推进我国导航定位技术的发展。

基于积分球冷却的小型化原子钟，作为新一代星载原子钟，已经广泛应用于时频的精密测量、量子相干操控研究。在本项目中，我们构建了一套上抛式积分球超高真空系统，实现了积分球内铷原子的深度冷却，并开展了一系列积分球内原子团的动力学研究。进一步的，我们研究了积分球内光子反冲诱导共振光谱，构建了多能级原子模型，阐述了其内部潜在的冷却机制，并用该光谱对积分球内冷原子团的温度进行了测量；研究了pump-probe光谱及光频移的相关物理现象，并提供了一种测量积分球内漫反射光场分布及其有效拉比频率的新手段。此外，我们构建了一套磁阱系统，开展冷铷原子的磁囚禁实验，实现了更高效的装载率；提出一种基于受激拉曼光谱测量磁场方向的新方法，实现了极高的角度和空间分辨率极高。 我们还发展了磁不敏钟跃迁的微波射频双光子技术，实现原子数的非绝热态转移。这些结果为新型积分球原子钟提供了一种崭新的研究方向和研究技术。