Correlation effects of chaotic and phase-diffusion fields on polarization beats in a V-type three-level system

The correlation effects of fourth-order on polarization beats in a V-type t hree-level system (PBVTS) are investigated using chaotic and phase-diffusio n models. It has been found that the temporal behaviour of the beat signal depends on the stochastic properties of the lasers and transverse relaxatio n rate of the transitions, and the modulation terms of the beat signal depe nd on the second-order coherence function, which is determined by the laser line shape. Since different stochastic models of the laser field affect on ly the fourth-order coherence function, they have little influence on the g eneral temporal modulation behaviour of the beat signal. The different role s of the phase fluctuation and amplitude fluctuation have been pointed out in the time domain. The fourth-order coherence function theory of chaotic f ield is of vital importance in PBVTS. The cases where the pump beams have e ither narrow band or broadband linewidth are considered and it has been fou nd that for both cases a Doppler-free precision in the measurement of the e nergy-level splitting between two states can be achieved. Finally, the diff erence between the PBVTS and DeBeer's ultrafast modulation spectroscopy is discussed as well from a physical viewpoint.