  The formation of dark states under interaction of degenerate atomic states
with incoherent broadband radiation (white light) is discussed. A simple
coupling scheme in a three level Lambda-system, which allows both qualitative
and quantitative analysis is discussed. We found a stationary solution of the
optical Bloch equations in a broad excitation line approximation that describes
the dynamics of the atom-white light interaction and demonstrated its identity
to a conventional dark state created with coherent laser fields. We than
examine the efficiency of the population transfer induced by broadband
radiation in a model Lambda-system and revealed that high efficiency (attaining
100 percent) of stimulated Raman adiabatic passage-like processes can be
achieved with certain temporal control of light polarization. The corresponding
criterion of adiabaticity was formulated and justified by means of numerical
simulations.
