What is Holography?
Holography is the creation of a light wave interference pattern recorded on film or other suitable surface that can produce a 3D image when illuminated.

How does it work?
Holography involves splitting a laser beam into two beams. The reference beam is spread by a lens and aimed via mirror directly at the film, while the object beam is spread and aimed at the object to be holographed. Because the object reflects some of the light onto the holographic film plate, the two beams interact, forming an interference pattern on the film. This pattern is the hologram. When the hologram is illuminated from the original direction of the reference beam, a 3D image of the object appears where the object was originally.

What's Holography used for?
•• holographic art
•• diffractive optics
•• security against forgery (e.g., credit card)
•• holographic interferometry, for measuring changes in the dimensions of an object
•• combining CAT scans into a 3D image
•• holographic computer memory storage