Polarization spectroscopy in rubidium and cesium
  We develop a theoretical treatment of polarization spectroscopy and use it to make predictions about the general form of polarization spectra in the alkali atoms. Using our model, we generate theoretical spectra for the D2 transitions in 87Rb, 85Rb, and 133Cs. Experiments demonstrate that the model accurately reproduces spectra of transitions from the upper hyperfine level of the ground state only. Among these, the closed transition F -> F' = F + 1 dominates, with a steep gradient through line center ideally suited for use as a reference in laser locking. 
M. L. Harris, C. S. Adams, S. L. Cornish, I. C. McLeod, E. Tarleton   and I. G. Hughes