Demonstration of a high-performance pulsed optically pumped Rb clock based on a compact magnetron-type microwave cavity

摘要

We demonstrate a high-performance pulsed optically pumped (POP) Rb vapor-cell clock based on a magnetron-type microwave cavity of only 44 cm~3 external volume. Using optical detection, an unprecedented 35% contrast of the Ramsey signal has been obtained. Both the signal-to-noise ratio (of 30000) and the estimated shot-noise limit of 1.7 × 10~(-14) τ~(-1/2) are at the same level as those found with a bigger cylindrical TE_(011) cavity (100cm inner volume) and are sufficient for achieving excellent clock stability. Rabi oscillations are measured and indicate a sufficiently uniform microwave magnetic field distribution inside the cavity. The instability sources for the POP clock's performance are analyzed. A short-term stability of 2.1 × 10~(-13) τ~(-1/2) is demonstrated which is consistent with the noise budget.