Polarization rotation spectral profiles for the D2 line of 87 Rb atoms: theory and experiment

We present a theoretical and experimental study of the polarization rotation of a linearly polarized probe beam scanning across all of the neighboring hyperfine levels (F e = 1 and 2) with a circularly polarized pumping beam resonant on the transition of the D2 line of 87Rb atoms. The experimental results match well with the results calculated from the full-level density matrix equations considering laser phase noise, which hinders observations of narrow lines with linewidths of ~90 kHz, as calculated in polarization rotation spectra for the first time.