Very few people in the comments seem to understand what holography is. A hologram is not a “3D display” that mimics a sci-fi movie or TV show. A hologram is photographic media / display technology that records and transmits phase as well as intensity of incident photons. By capturing all the properties of the electromagnetic field that strikes the film, and re-emitting the same EM wave when stimulated, the hologram ends up being a full “3D picture” because after all, the light that hits your eyes ends up being the same as if you were looking at the actual scene. But that’s a consequence, not the defining property.
3blue1brown has a great explainer video on what holograms are: https://youtu.be/EmKQsSDlaa4