The optical system of the fountain clock

This paper present an optical system for Cs atomic fountain clock that is located on a 1.2 m×1.2 m optical table. Taking advantage of this system, we trap about 10
⁸
cesium atoms in the magneto-optic trap (MOT) and get the Ramsey fringe of the fountain by scanning the microwave frequency of the interrogation cavity. The full-width at half-maximum of the central fringe (FWHM) is 1.4 Hz.