Pulsed Optically Pumped Atomic Clock With Zero-Dead-Time

By alternatively operating two pulsed optically pumped (POP) atomic clocks, the dead time in a single clock can be eliminated, and the local oscillator can be discriminated continuously. A POP atomic clock with a zero-dead-time (ZDT) method is then insensitive to the microwave phase noise. From tau = 0.01 to 1 s, the Allan deviation of the ZDT-POP clock is reduced as nearly tau(-1), which is significantly faster than tau(-1/2) of a conventional clock. During 1-40 s, the Allan deviation returns to tau(1/2). Moreover, the frequency stability of the ZDT-POP clock is improved by one order of magnitude compared with that of the conventional POP clock. We also analyze the main factors that limit the short-term frequency stability of the POP atomic clock. Published by AIP Publishing.