A hologram is an optical representation of an object. Unlike photography, a hologram is three-dimensional, capturing both the volume of the object and the change in perspective when viewed from different angles.
A hologram is often confused with a 3D image, but a 3D image appears three-dimensional only from one specific viewpoint, whereas a hologram appears three-dimensional from any angle. Holograms and 3D images are created using fundamentally different methods: to create a 3D image, two images are prepared (one for the right eye and one for the left), and they are combined.
Thanks to the stereo effect, the brain perceives such an image as three-dimensional. Holograms, on the other hand, are created by recording the structure of the wave reflected from the object (including its amplitude and phase) using a laser. This method is called "holography", derived from the ancient Greek word "I write everything."
In science fiction films like Star Wars or Iron Man, holograms are depicted as three-dimensional images of people or objects visible to the naked eye, with which you can interact.
While in the world of cinema we have long been accustomed to such depictions, true holograms as seen in films do not yet exist in reality. However, scientists are actively researching in this direction, and there are technologies that can "simulate" holograms.
One of these optical illusions, called "Pepper's Ghost", has been used to create performances featuring "resurrected" artists like Tupac Shakur, Michael Jackson, and Roy Orbison. In everyday life, holograms, which are iridescent three-dimensional images, can be found on items such as currency bills, credit cards, official documents, as well as on various consumer goods and excise stamps.