  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.
