Toward a cesium frequency standard based on a continuous slow atomic beam: preliminary results

A continuous beam of slow cesium atoms was produced from a thermal atomic beam by laser cooling. This beam was used as the source for the frequency standard. The Rabi-Ramsey spectrum was observed with the cold atomic beam. The Ramsey fringe of 62-Hz linewidth was obtained from a 21-cm-long microwave cavity. We found that the Rabi-Ramsey spectrum exhibited little dependence on the frequency of the pumping laser because of the long interaction time with the pumping light.