Fig. 1

Schematics of the experiment. a The unit cell of undoped GaAs with four different (111) planar cuts intersecting different sites of its zinc blende structure. A {111}-type reflection, actually (-1-1-1), was chosen because the Ga(Mn) and As atoms do not lie together on these planes, with the type of atom intersected by each plane indicated in the figure. b A schematic side view of the experimental geometry, where the oscillations of the excitation field along the [111] direction are depicted and different atomic species are excited with a different intensity of primary radiation depending on the position of the nodes and antinodes of the standing wave