Coherent effects on the Zeeman sublevels of hyperfine states in optical pumping of Rb by monomode diode laser

Experimental examination of the coherent population trapping that can be established on the D-1 and D-2 Lines of Rb at a single hyperfine transition using the Zeeman sublevels of the hyperfine states is reported here. The coherent effects have been examined in Hanle configuration, exciting the Rb vapour in a glass cell by linearly polarized monomode laser beam. Experimental evidence is presented of subnatural width resonances in the fluorescence and the transmitted through the Rb cell laser power, which are due to the process of coherent population trapping on the Zeeman sublevels. In case of degeneracy of the ground level F-g lower than that of the excited level F-e, bright peaks in the fluorescence and increased absorption have been observed, together with the well known dark resonances for F-g greater than or equal to F-e. The peaks in the fluorescence in the Hanle-effect configuration have been observed for the first time. (C) 2000 Published by Elsevier Science B.V. All rights reserved.