How does a Hologram works?

How does a Hologram works?

Holograms are working by recording the patterns of light and interference patterns on holographic film. You see light is a wave as with any wave, light has peak and drain. The peak is the top of the wave and the drain, the bottom. When two waves meet up, one of a few things occur:

1.     The peak and drain concur. When this occur the amplitude of the wave doubles. This is called constructive interference
2.     The two waves are entirely out of sync. This causes the crests and troughs to overlap. If the two waves had the same amplitude, they will cancel each other out completely. This is destructive interference.
3.     The last possibility is when the waves aren’t in perfect sync, or perfectly inverse. When this happens you get a unique pattern of interference.

As the light chosen up by each eye is a small different, and because the interference pattern is different for every light beam that hits the hologram, it comes out differently. Because the eyes pick up slightly dissimilar versions of the image, the brain is fooled into seeing a 3D image. So in reality this is mainly an optical illusion.