Effects of field correlation on polarization beats - art. no. 053819

We have employed a second-order coherence function theory to study the effe ct of laser coherence on polarization beats in four-level system (PBFS). It is found that the temporal behavior of the beat signal depends on the stoc hastic properties of the lasers and transverse relaxation rate of the trans ition. The cases that pump beams have either narrow band or broadband linew idth are considered and it has ken found that for both cases a Doppler-free precision in the measurement of the energy-level splitting between two exc ited states which are: dipolar forbidden from the ground state can be achie ved. We have also studied the asymmetric behavior of the polarization beats , and attributed this asymmetry to the shift of the zero time delay which i s due to the dispersion of the optical components.