Coherent population trapping resonances in Cs atoms excited by elliptically polarized light

Coherent population trapping (CPT) resonances study in Hanle configuration is reported for different polarizations of the exciting light field, on the D-2 line of Cs atoms. While for linear/circular polarization dip/peak in the fluorescence is registered, in case of elliptical polarization, a complex shape resonance is evidenced experimentally, whose profile strongly depends on the ellipticity of polarization. A theoretical model is proposed and developed, which includes the influence on the resonance of polarization ellipticity, transverse magnetic field, and spatial intensity profile of the laser beam. Good agreement is found between the theoretical and experimental results. The reported results allow one to accomplish more profound than in previous research analysis of the CPT resonances behavior pointing out their sensitivity to the light polarization and power as well as to transverse magnetic fields. The presented study is of general importance for the wide application of the coherent resonances in high resolution spectroscopy and precise measurements. The purity of linear/circular polarization of the light needed in different applications can be estimated implementing the proposed model.