We report an experimental demonstration that shows that the spatial structure carried by engineered coherent superpositions of light beams with orbital angular momentum can be mapped into the nonlinear polarization induced in a cloud of cold cesium atoms. The structure of such polarization was revealed by nearly degenerate four-wave-mixing processes.
Barreiro, S., Tabosa, J., Juan P. Torres, Deyanova, Y., Torner, L. Four-wave mixing of light beams with engineered orbital angular momentum in cold cesium atoms. "Optics letters", Juliol 2004, vol. 29, núm. 13, p. 1515-1517.