  We demonstrate the non-dispersive deflection of an optical beam in a
Stern-Gerlach magnetic field. An optical pulse is initially stored as a
spin-wave coherence in thermal rubidium vapour. An inhomogeneous magnetic field
imprints a phase gradient onto the spin wave, which upon reacceleration of the
optical pulse leads to an angular deflection of the retrieved beam. We show
that the obtained beam deflection is non-dispersive, i.e. its magnitude is
independent of the incident optical frequency. Compared to a Stern-Gerlach
experiment carried out with propagating light under the conditions of
electromagnetically induced transparency, the estimated suppression of the
chromatic aberration reaches 10 orders of magnitude.
