Squeezing and Quantum Noise Quenching in Optically Pumped Atomic Clocks

Xuejie Li, Yuhan Yan, Bowen Yang +4 more

Gongxun Dong, 林锦达 Lin Jinda, 张 松 Zhang Song +2 more

Claus Benkert, Marlan O. Scully, János A. Bergou +1 more

Atomic coherence, when combined with a reduction of pump noise, can lead to significant noise quenching in lasers and even squeezing in masers. Furthermore, this noise reduction can be modified in an interesting way by atomic broadening.

Haixiao Lin, Jianliao Deng, Jinda Lin +2 more

In general, the linewidth of the Ramsey central fringe (RCF) is equal to 1/(2T), where T is the Ramsey free-evolution time. We demonstrate that the RCF linewidth of a pulsed optically pumped (POP) atomic clock with orthogonal polarization detection based on the magneto-optical rotation effect can be narrowed down to 1/(4T). The Allan deviation of the POP atomic clock decreases from 2.4×10−13τ−1/2 to 1.4×10−13τ−1/2. This corresponds to an improvement in the frequency stability by about 60%. We also estimate the main noise sources that limit the short-term frequency stability of the POP atomic clock.

Boris Braverman, Akio Kawasaki, Vladan Vuletić

Weibin Xie, Qing Wang, Xuan He +8 more

Herein, we report the scheme of an optically pumped atomic clock based on a cold cesium atomic beam source. We propose the laser system and physical mechanism of this atomic clock, wherein the atomic beam travels in an upper parabolic trajectory, thereby eliminating the light shift effect. In the experiments, when the length of the free evolution region was 167 mm, the line width of the Ramsey fringe was 37 Hz. When the expected signal-to-noise ratio of the Ramsey fringe that can be achieved is 36,000, the expected short-term frequency stability is about 3.6 × 10–14/√τ, which is significantly higher than that of a conventional optically pumped cesium clock of similar volume.