eli5 How do holograms work?

Question

eli5 How do holograms work?

In: 0

Answer 1

Holography records the interference pattern from two separate light sources into a substrate. Light of a specific wavelength (usually from a laser) is reflected off an object toward the substrate, while a second reference light source shines directly onto the substrate.

These separate light sources interfere with each other, creating an interference pattern which etches itself onto the substate surface.

When a light source similar to the reference source shines onto the recorded interference pattern, the light reflected away resembles the reflected half of the light field that produced the hologram.

Because the interference pattern is produced from a field of light, the actual image seen depends on the eye’s relative position to the hologram, just as the image of the real object changes as you move around it.
Thus, the reflected light field produces an illusion of a 3 dimensional object. We call this illusion a “hologram.”