This page is still in progress.Hologram of a single photon. R. Chrapkiewicz, M. Jachura, K. Banaszek and W. Wasilewski in Nature Photon. 10:576 (2016).  What the paper says!?

This important paper introduces single-photon holography based on the HOM effect that interferes an unknown photon with a controlled one. The spatial structure of the unknown photon can thus be reconstructed, both phase and intensity.