Polarization rotation with electromagnetically induced transparency in a V-type configuration of Rb D1 and D2 transitions

Polarization rotation in electromagnetically induced transparency (PREIT) in rubidium vapour at room temperature has been studied experimentally as well as theoretically in the absence of any magnetic field. PREIT is observed for both Rb-85 and Rb-87 combining the D-1 and the D-2 transitions with a V-type configuration. For Rb-85, two EIT peaks and for Rb-87, one EIT peak were observed. Nonlinear characteristics of the variations of the angle of rotation corresponding to the EIT position were observed for both the isotopes of Rb. We have modelled a four level system to explain the occurrence of the double EIT in case of the Rb-85 and the occurrence of one EIT peak for Rb-87. The rotation of plane of polarization of the probe beam can be further explained with this model. The characteristic behaviour of the variation of rotation corresponding to the EIT position from theoretical analysis has matched well with the experimental observations. A sharp rotation with a high signal to noise ratio in the vicinity of the EIT can be used as a modulation free and noise insensitive signal for the frequency stabilization.