Application of Holography

Holography is widely used. The application of holographic technology in photography is far superior to ordinary photography. Ordinary photography is based on the principle of lens imaging, which projects a three-dimensional scene onto a flat photosensitive floor to form a light intensity distribution. The recorded photos have no stereoscopic effect, because the images obtained from the photos are the same from all angles. Holography reproduces the object light wave accurately. When we "look" at the light wave of this object, we can observe different sides of the reproduced stereoscopic image from all angles, just like seeing a real object, with depth of field and parallax. If we shoot two Mercedes-Benz cars side by side, then when we change the observation direction, the blocked part of the latter car will be exposed. No wonder people are excited about the hologram taken by a Mercedes-Benz car in the exhibition: "It's amazing to see the reappearance of the car, as if you can get on the Mercedes-Benz as soon as you pull the door!" A hologram is equivalent to many ordinary photos, shot from multiple angles and focused. In this sense, the information content of a hologram is equivalent to 100 or 1000 ordinary photos. When you look at the hologram surface with a high-power microscope, you can see complex stripes, but you can't see the image of the object at all. These fringes are formed by the interference between the object light wave emitted by the laser irradiation object and the standard light wave (reference light wave), and are recorded on the plane photosensitive substrate, that is, the object light wave is "frozen" by the coding method. Once the illumination light wave similar to the reference light wave is irradiated, the imaging light wave will be diffracted, just like the original light wave is released again. So the principle of holography can be expressed in eight words: "interference recording, diffraction reproduction".