Properties of an optically pumped cesium-beam frequency standard with /spl Phi/=/spl pi/ between the two oscillatory fields

The properties of optically pumped cesium-beam resonators showing a phase difference, /spl Phi/, of /spl pi/ between the two oscillatory fields are analyzed. They are compared with those occurring with /spl Phi/=0, when the interrogation signal is slowly square-wave frequency modulated. The value of the operating parameters which optimizes the resonator properties is given for /spl Phi/=0 and /spl pi/,taking into account the effect of the noise sources which perturb the atom detection. It is shown that the design with /spl Phi/=/spl pi/ is superior. It provides a better frequency stability and smaller frequency offsets. The conclusion holds for short as well as long tubes.<
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