PURE 2-ATOM SQUEEZED STATE IN SPONTANEOUS EMISSION FROM 2 NONIDENTICAL ATOMS

We calculate the stationary state of the system of two non-identical t wo-level atoms driven by a finite-bandwidth two-mode squeezed vacuum. It is well known that two identical two-level atoms driven by a broadb and squeezed vacuum may decay to a pure state, called the pure two-ato m squeezed state, and that the presence of the antisymmetric state can change its purity. Here, we show that for small interatomic separatio ns the stationary state of two non-identical atoms is not sensitive to the presence of the antisymmetric state and is the pure two-atom sque ezed state. This effect is a consequence of the fact that in the syste m of two non-identical atoms the antisymmetric state is no longer the trapping state. We also calculate the squeezing properties of the emit ted field and find that the squeezing spectrum of the output field may exhibit larger squeezing than that in the input squeezed vacuum. More over, we show that squeezing in the total field attains the optimum va lue which can ever be achieved in the field emitted by two atoms.