Microwave Pulse-Coherent Technique-Based Clock With a Novel Magnetron-Type Cavity

We report a high-performance pulsed optically pumped (POP) Rb clock based on a novel magnetron-type microwave cavity. The cavity has a volume of 30 mL, enabling a highly homogenous microwave field distribution. With the laser frequency tuning to the ground-state hyperfine level F = 2 of the D
₂
line, we observe a Ramsey fringe contrast of 52% in terms of optical absorption detection. The resultant shot noise limit is estimated to be 1.6 × 10
^-14
τ
^-1/2
. The clock frequency stability is measured as 2.3 × 10
^-13
τ
^-1/2
(1-100 s), which is limited by the relative intensity noise of the light.