Characteristics of absorption and dispersion for rubidium D2 lines with the modulation transfer spectrum.

Absorption and dispersion signals of D2 lines of rubidium atoms in a vapor cell have been experimentally investigated with the modulation transfer spectrum (MTS). Normal dispersion was observed at the transitions of Fg ? Fe = Fg - 1 and Fg ? Fe = Fg; anomalous dispersion, at transitions of Fg ?Fe = Fg + 1; and crossover resonance, by the transitions of Fg ?Fe = Fg - 1 and Fg ? Fe = Fg. The signal lineshape of the MTS and the detector phase are addressed accurately.