Think holograms and some famous movies come to mind. But the technology that makes those 3D images look so real is also used in everyday objects too, like credit cards, driver’s licenses, and plenty of security tools.
A hologram is a representation of a surface. Initially they were made based on a real object using laser technology that recorded 3D objects and transferred the images to a photographic medium, like silver halide. By virtue of this cumbersome process, holographs took a while to find their way to more diverse industries than film.
Once it became possible to create a hologram using computers with dedicated software, the graphical output, now known as a computer generated hologram (CGH) could be transferred to glass and other types of materials. But even more important, was that the newly created CGH did not depend on a real object being present the way the original holograms did. Theoretically, using the right mathematical calculations and a knowledge of what an ideal surface should look like, it was possible to create a representation of a surface that was nearly perfect even though the object was not right in front of you. This made CGH a natural extension of interferometry.