Optical cloning of arbitrary images beyond the diffraction limits

Abstract: Cloning of arbitrary images encoded onto the spatial profile of a laser beam onto that of a second beam is theoretically investigated. The two fields couple to an atomic lambda system in a coherent population trapping configuration. In particular, the case in which the probe and control fields are of comparable strength is considered. By considering more and more complex structures, we eventually find that our method is suitable to clone arbitrary images, which we demonstrated by a full numerical simulation of the propagation dynamics of both applied fields in the atomic medium, with the three letters "CPT" encoded on the initial control field profile. We find that the cloned structures have feature sizes reduced by about a factor of 2 compared to the initial images, consistent with a recent related experiment.