High-order Field Sqeezing Base On Dark Resonances

Atomic coherence effect is a hot topic which can lead to a series of important phenomena.For example,Coherent population trapping.The common mechanism for it is dark state resonance.When two beams of optics fields interact with on two-photon resonance with three-level A-type atoms.the atoms will be trapped into a coherent superposition state,which called the dark state.The effect is called dark-state resonance effect.This paper is about the investigation of the atomic spin squeezing and the quan-tum correlation between the atoms and the cavity in a three-level A-type system.we choose symmetrical detuning to induce nonlinearities.Then we use dressed state pre-sentation to describe the whole system. And we introduce the Bogoliubov modes of the fields and atom spins.We can obtained two-mode squeezing and entanglement of the field and atom spins by the dissipation effect of Bogoliubov modes.Bseed on the dissipation effect of the Bogoliubov modes,we have a qualitative analysis:the light en-tanglement and spin squeezing can be obtained when the detuning is confined within the special ranges.We get the numerical results,which fit well with our qualitative analysis,explaining Bogoliubov modes dissipation is a direct mechanism to generate the squeezing and entanglement.Finally, we given the expression of the fluctuations of the high-order qualities of the cavity field on the basis of the previous work.high-order squeezing and entangle-ment can be also obtained in the special ranges.