  The interaction of spatially structured light fields with atomic media can
generate spatial structures inscribed in the atomic populations and coherences,
allowing for example the storage of optical images in atomic vapours.
Typically, this involves coherent optical processes based on Raman or EIT
transitions. Here we study the simpler situation of shaping atomic populations
via spatially dependent optical depletion. Using a near resonant laser beam
with a holographically controlled 3D intensity profile, we imprint 3D
population structures into a thermal rubidium vapour. This 3D population
structure is simultaneously read out by recording the spatially resolved
fluorescence of an unshaped probe laser. We find that the reconstructed atomic
population structure is largely complementary to the intensity structure of the
control beam, however appears blurred due to global repopulation processes. We
identify and model these mechanisms which limit the achievable resolution of
the 3D atomic population. We expect this work to set design criteria for future
2D and 3D atomic memories.

Atomic Physics;Optics