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-metal 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.