Effect of atomic diffusion on the Raman-Ramsey CPT resonances

TL;DR

This study experimentally examines how atomic diffusion affects the shape and performance of CPT and Raman-Ramsey resonances in Rb vapor cells, with implications for atomic clock stability.

Contribution

It provides new insights into the influence of atomic diffusion on CPT and Raman-Ramsey resonances and their impact on atomic clock performance.

Findings

Diffusion modifies resonance shapes in Rb vapor cells.

Raman-Ramsey did not outperform steady-state CPT at moderate buffer gas pressures.

Atomic clock stability is not improved by Raman-Ramsey under certain conditions.

Abstract

We experimentally investigated the characteristics of two-photon transmission resonances in Rb vapor cells with different amount of buffer gas under the conditions of steady-state coherent population trapping (CPT) and pulsed Raman-Ramsey (RR-) CPT interrogation scheme. We particularly focused on the influence of the Rb atoms diffusing in and out of the laser beam. We showed that this effect modifies the shape of both CPT and Raman-Ramsey resonances, as well as their projected performance for CPT clock applications. In particular we found that at moderate buffer gas pressures RR-CPT did not improved the projected atomic clock stability compare to the regular steady-state CPT resonance.