Ground state Zeeman coherence effects in an optically pumped cesium beam

Abstract The population trapping in a cesium beam induced at low magnetic field by σ polarized light from a broadband laser diode has been investigated. The dip observed in the fluorescence is interpreted in terms of Zeeman coherences in the ground state which trap the atomic populations. A quantitative description is given through the analysis of the atom light interaction with a rate equation model including Zeeman coherences.