Influence of light on spin diffusion in weak magnetic fields

Abstract

We demonstrate that optical illumination strongly influences spin transport in $n$-type GaAs. Specifically, increasing the power density of optical spin pumping results in a significant expansion of the spin-diffusion profile. A further means of manipulation is the application of a weak transverse magnetic field, which strongly increases the spin flow out of the excitation spot. These effects are directly monitored in spin-imaging experiments and spatially resolved Hanle measurements.