Searching for alignment-to-orientation conversion in the ground state of atomic Cs with circularly polarized laser probe

TL;DR

This paper investigates the potential to observe angular momentum alignment-to-orientation conversion (AOC) in the ground state of alkali atoms, combining theoretical modeling with experiments on cesium using laser spectroscopy.

Contribution

It introduces a comprehensive model including hyperfine interactions, magnetic field effects, and laser coherence, and provides experimental analysis of AOC signals in cesium atoms.

Findings

Theoretical model explains features of AOC signals in alkali atoms.

Experimental detection of AOC in cesium using circularly polarized laser probe.

Discussion of systematic errors due to weak AOC signals.

Abstract

In this study we explored the possibilities for observing the angular momentum alignment-to-orientation conversion (AOC) in the ground state of various alkali metals: K, Rb, Cs. For theoretical analysis we used a model that is based on the Optical Bloch equations for the density matrix. Our model includes the interaction of all neighboring hyperfine levels with laser radiation, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. Additionally we simulated signals where the ground- or the excited-state coherent processes were numerically switched off in order to determine the origins of the features of the obtained signals. We also performed experiments on Cs atoms with two laser beams: a linearly polarized Cs $D_1$ pump and circularly polarized Cs $D_2$ probe. We used the pump beam to create angular momentum alignment in the ground state and observed the transmission signal of the probe beam as we changed the magnetic field. A detailed analysis of the experimentally obtained transmission signal from a single circularly polarized probe laser component is provided. Finally, prospects for observing AOC conversion experimentally are discussed, as well as experiments were even a weak AOC signal could lead to systematic errors.