  We report the transfer of phase structure, and in particular of orbital
angular momentum, from near-infrared pump light to blue light generated in a
four-wave-mixing process in 85Rb vapour. The intensity and phase profile of the
two pump lasers at 780nm and 776nm, shaped by a spatial light modulator,
influences the phase and intensity profile of light at 420nm which is generated
in a subsequent coherent cascade. In particular we oberve that the phase
profile associated with orbital angular momentum is transferred entirely from
the pump light to the blue. Pumping with more complicated light profiles
results in the excitation of spatial modes in the blue that depend strongly on
phase-matching, thus demonstrating the parametric nature of the mode transfer.
These results have implications on the inscription and storage of
phase-information in atomic gases.
