Optical holography
Microwave holography - Principle and applications

Optical holography is a technique for recording and reproducing three-dimensional images using coherent light, usually from a laser. It is based on the principle of interference between a reference beam and a beam illuminating the object, thus creating an interference pattern recorded on a photosensitive medium (Figure1a). Unlike conventional photography, which only captures light intensity, holography also records the phase of the light, allowing the relief and depth of the object to be faithfully reproduced. When a coherent light beam illuminates the recorded hologram, it recreates the original light wave, giving the illusion of a floating three-dimensional image (Figure