  We demonstrate theoretically that a coherent manipulation of electron spins
in low-dimensional semiconductor structures with spin-orbit coupling by
infrared radiation is possible. The proposed approach is based on using a
dipole force acting on a two-level system in a nonuniform optical field,
similar to that employed in the design of the cold atoms diode. For ballistic
electrons the spin-dependent force, proportional to the intensity of external
radiation, leads to a spin-Hall effect and resulting spin separation even if
the spin-orbit coupling itself does not allow for these effects. Achievable
spatial separation of electrons with opposite spins can be of the order of
several tenth of a micron, an order of magnitude larger than can be produced by
the charged impurity scattering in the diffusive regime.
