Ghost Imaging with Atoms
Ghost imaging is a technique - first realized in quantum optics - that uses the cross-correlation between particles in two separate beams, one of which passes through the object to a bucket (single-pixel) detector, while the second is measured by a high spatial resolution (multi-pixel) detector but never interacts with the object. Neither detector can reconstruct the image independently. Here we report on the first realisation of ghost imaging of a macroscopic object using massive particles. In our experiment, the two beams are formed by correlated pairs of ultracold metastable helium atoms originating from two colliding Bose-Einstein condensates (BECs). We use higher-order Kapitza-Dirac scattering to generate the large number of correlated atom pairs required, enabling the creation of a ghost image with good visibility and sub-millimetre resolution.