High performance flywheel source for atomic fountains and advanced metrology applications

Atomic fountain frequency standard have the potential to reach a frequency stability of about 10-¹⁴ _T-1/2, if the interrogation oscillator frequency noise which degrades the stability via the "Dick effect " ([2, 7]) is made negligible. In this aim a Sapphire Cryogenic Oscillator (SCO) is used as very low noise frequency source sigma_y(T) les 1 - 2 times 10^-15 1 s < T < 1000 s. In this paper, we describe a low phase/frequency noise flywheel source for atomic fountains and other demanding metrological applications (cold atom inertial sensors, optical frequency standards, optical synthesizer based on femto-second laser).