THE weird quantum property called “entanglement” can be used to create quantum holograms. A pair of entangled photons always know the state of each other no matter how far apart they are. Quantum holograms use this spooky property to let us see 3D images of hidden objects.
In classical holography, a laser beam reflected off an object interferes with a reference beam, and the interference pattern is recorded on a photographic plate. This pattern creates a hologram that you can see by illuminating the plate with a laser.
If the object is hidden you cannot collect the reflected light, but…
