Derivation of CPT resonance signals from density-matrix equations with all relevant sublevels of Cs atoms and confirmation of experimental results

TL;DR

This paper develops a detailed density-matrix model for CPT resonance in Cs atoms, accurately predicting experimental signals by considering all relevant hyperfine Zeeman sublevels and their interactions.

Contribution

It introduces a comprehensive multi-level atomic model for CPT resonance in Cs atoms, bridging theoretical predictions with experimental observations.

Findings

Numerical solutions match experimental CPT resonance signals.

The model accurately predicts amplitude and shape of transmitted light.

All relevant sublevels are essential for precise modeling.

Abstract

Coherent-population-trapping resonance is a quantum interference effect that appears in the two-photon transitions between the ground-state hyperfine levels of alkali atoms and is often utilized in miniature clock devices. To quantitatively understand and predict the performance of this phenomenon, it is necessary to consider the transitions and relaxations between all hyperfine Zeeman sublevels involved in the different excitation processes of the atom. In this study, we constructed a computational multi-level atomic model of the Liouville density-matrix equation for 32 Zeeman sublevels involved in the $D_1$ line of $^{133}$Cs irradiated by two frequencies with circularly polarized components and then simulated the amplitude and shape of the transmitted light through a Cs vapor cell. We show that the numerical solutions of the equation and analytical investigations adequately explain a variety of the characteristics observed in the experiment.