  We discuss methods for imaging the nonequilibrium spin polarization of
electrons in Fe/GaAs spin transport devices. Both optically- and
electrically-injected spin distributions are studied by scanning
magneto-optical Kerr rotation microscopy. Related methods are used to
demonstrate electrical spin detection of optically-injected spin polarized
currents. Dynamical properties of spin transport are inferred from studies
based on the Hanle effect, and the influence of strain on spin transport data
in these devices is discussed.
