  We propose a method for spatially re-routing single photons or light in a
coherent state with small average photon number by purely electronic means,
i.e. without using mechanical devices such as micro-mirror arrays. The method
is based on mapping the quantum state of the incoming light onto a spin-wave in
an atomic ensemble as is done in quantum memories of light. Then the wavevector
of the spin-wave is modified in a controlled way by an applied magnetic field
gradient. Finally, by re-applying the same control beam as for storing, the
signal pulse is released in a new direction that depends on the deflected
wavevector of the spin-wave. We show by numerical simulation that efficiencies
can be achieved for arbitrary deflection angles in the plane that are
comparable with simple photon storage and re-emission in forward direction, and
propose a new method for eliminating the stored momentum as source of
decoherence in the quantum memory. In a reasonable parameter regime, the
re-routing should be achievable on a time-scale on the order of few to
$\sim100$ microseconds, depending on the deflection angle. The shifts in the
wavevector that can be achieved using the Zeeman-effect, with otherwise minimal
changes to the spin-wave, can also be used to complement existing ac-Stark
spin-wave manipulation methods.
