Spectral dependence of polarization of cesium atoms during pumping by a narrowband semiconductor laser

It is found in an experiment with narrowband laser pumping of Cs atoms by light of the D ₂-line that the spectral dependence of the polarization of atoms significantly differs from the spectral dependence of the light absorption by nonpolarized atoms. The difference lies in a partial resolution of the hyperfine structure of the excited 6² P _3/2 state, which remains unresolved in the case of nonpolarized atoms. The shape of the spectral dependence of the atom polarization observed upon pumping with circularly polarized light differs from that in the case of the linear polarized pumping and depends strongly on the buffer gas pressure, which allows one to obtain experimental information on collisional relaxation in the excited state. Calculation for a cell with antirelaxation coating and a cell with helium (6-Torr pressure) gives spectral dependences that are qualitatively consistent with experiment.