Creation of atomic coherent superpositions in manifolds of levels without multi-photon resonance

We propose a scheme for creating atomic coherent superpositions via stimulated Raman adiabatic passage in a Lambda-type system where the final state has twofold levels. In the employ of a control field, the presence of double dark states leads to two arbitrary coherent superposition states with equal amplitude but inverse relative phase without the condition of multi-photon resonance. In particular, two orthogonal maximal coherent superposition states are created when the control field is resonant with the transition of the twofold levels. This scheme can also be extended to manifold Lambda-type systems.