The Nonclassical Properties Of Optical Field In Kerr Medium About Effects Of Coherent State And Superposed Two-level Atom

Odd and even coherent states are two vertical normalizing eigenstates of thesquare of annihilation operators in the optical field,which have two differentnon-classical properties respectively, anti-bunching and squeezing effect. In this paper,let a superposed two-level atom with appropriate velocity pass successively through acavity with coherent optical field and a Ramsey strap. Then the coherent state that weneed is got by selective measure in a large detuning limit. The states|Ψ₁ >&| Ψ₂>will deviate from odd-even coherent state when the cavity is filled with nonlinear Kerrmedium and the Stark effect is considered. Thus, we study the effect of Kerr mediumand the Stark effect respectively by acting on non-classical properties ofstate|Ψ₁ >&| Ψ₂>. Furthermore, the properties of time-evolution of states|Ψ₁ (t )>&| Ψ₂ ( t )> affected by Kerr medium and the Stark effect are also discussed.By means of the method of time-evolution operator , eigenvalues andeigenfunction and numerical calculation, we can find that in the chart of|Ψ₁ >,| Ψ₂>,altering with average of phonon-number, anti-bunching effect of state | Ψ₂> isweaken but that of the state |Ψ₁ > is strengthened with parameter χ/λ enhancing orthe ratio of β₂/β₁ weakening and in the meantime squeezing effect is weaken.In the chart of state |Ψ₁ (t )>,| Ψ₂ ( t )> evolving with time, the phenomenon ofperiodical collapse-revival of the 2nd-order coherent degree and squeezing effects ofoptical field appears clearly with the increase of average photon numbers under thecondition of resonance. The revival time is lengthened with the detuningparameter â–³/λ, and that is shortened under the conditions of parameter χ/λ orβ₁ &β₂ increasing till the phenomenon of periodical collapse-revival disappears andremains the common oscillation chart.