A magneto-optically pumped cesium beam clock using monochromatic light

Abstract

Compact cesium beam clocks are widely utilized in various applications. In contemporary commercial cesium clocks, two primary approaches are employed: the magnetically selected state scheme and the optical pumping scheme. Here, we propose a magneto-optically pumped cesium beam clock with a frequency stability of 2.3×10−12τ−1/2. In this scheme, the pumping light and state selection magnet are both used for the preparation of atomic states. In the magnetic field of the state selection magnet, the relationship between pumping efficiency and laser frequency, laser power, and laser position has been investigated. Eventually, we find a position that allows the laser to resonate with cyclic transition line |F=3⟩−|F′=2⟩ to pump almost all of the atoms |F=3⟩ to state |F=4⟩. Therefore, we can pump and detect atoms without the use of an AOM. This approach not only combines the advantage of low atomic velocity from the magnetically selected state scheme and the high atomic utilization efficiency from the optical pumping scheme but also simplifies the scheme of optically pumped cesium beam clock. In addition, this physical system can also facilitate the investigation of the shift in cesium atomic energy levels under strong magnetic fields.