Optical pumping and electromagnetically induced transparency in a lithium vapour

We report the first study of electromagnetically induced transparency (EIT) on the D1 and D2 lines of Li-7 in a vapour cell. The effect of different polarizations, background gas pressures and experimental designs on the dark resonance are examined. It is found that EIT is more prominent on the D1 line than on the D2 line and is present at the D2 transition under incident orthogonal linearly polarized fields and parallel circularly polarized fields, but absent for parallel linearly polarized fields and for orthogonal circularly polarized fields. It is shown that the contrast of the dark resonances can be affected by the presence of an inert background gas. An analysis of a further nine resonances observed at the D1 transition and three resonances at the D2 transition is presented.