Performance demonstration of a compact, single optical frequency Cesium beam clock for space applications

Observatoire de Neuchatel has developed a compact optically-pumped cesium beam frequency standard in the frame of an ESA-ARTES 5 project. The simplest optical scheme, which is based on a single optical frequency for both preparation and detection processes of atoms, has been chosen to fulfill reliability constraints of space applications. With the last evolution of our laboratory demonstrator, we have measured a frequency stability of sigma_y=1.14 times10^-12 tau^-1/2, which is compliant with the Galileo requirement and our frequency stability goal of sigma_y=1.14 times10^-12 tau^-1/2. Present performance limitations are discussed and further improvements are proposed to possibly increase the frequency stability.