Analysis of the noise sources in an optically pumped cesium beam resonator

The main noise sources that affect the clock signal detection in an optically pumped cesium beam resonator are determined and their influence on the clock S/N ratio is evaluated. The following noise sources are taken into account: atomic shot noise, fluorescence photon noise, laser frequency noise, and clock signal detection noise. A theoretical model that predicts the variations of the S/N ratio as a function of different parameters characterizing the atom-laser interaction is developed. The main conclusion concerns the saturation of S/N value for high atomic flux due to laser frequency fluctuations. All the theoretical predictions were experimentally verified