Electromagnetically Induced Transparency In Rydberg Atom Gas With Finite Doppler Broadening

Electromagnetically induced transparency(EIT),as the quantum coherence effects caused by the interaction of the light and matter have attracted much attention.The electromagnetically induced transparency has been applied in various fields: coherent population trapping(CPT),enhancement of Kerr nonlinearity,halted light.Recently,researchers try to extend the electromagnetically induced transparency to the Rydberg atomic ensemble.It is worth emphasizing that the Rydberg electromagnetically induced transparency can provide us better opportunity to control the light.However,most of the systems are ultra cold Rydberg atomic ensemble,and most works ignored the influence of temperature.In fact the Doppler effect caused by residual temperature in the system cannot be ignored.The main purpose of our work is to study the effect of Doppler broadening on steady-state optical response of Rydberg atomic ensemble.In previous works,researchers have introduced the calculation method of Doppler broadening in the general atomic ensemble under the electromagnetically induced transparency mechanism.Super atom model as one of the methods to deal with electromagnetically induced transparency in Rydberg atomic ensemble.In our work we consider the Doppler effect in the calculation of the SA beyond the weak field approximation.We find that the residual thermal effects of atoms(?mK)will weaken the nonclassical properties of probe photons.Furthermore,Doppler effect under the co-propagation case has intense destruction to the coherence of the system,but the count-propagation case has partial elimination of Doppler effect.