Pulsed Optically Pumped Rubidium Clock With High Frequency-Stability Performance

In this paper, we present the performance of a vapor-cell rubidium frequency standard working in the pulsed regime, in which the clock signal is represented by a Ramsey pattern observed on an optically detected laser absorption signal. The main experimental results agree with previously reported theoretical predictions. In particular, we measured a relative frequency stability of σ_y (τ) ≈ 1.6 × 10¹³-τ^-1/2 for integration times, τ, up to 200 s, which represents a record in short-term stability for a vapor-cell clock. We also discuss the most important physical phenomena that contribute to this result.