What principle of light is used by holographic technology?

Holographic technology utilizes the principle of light interference.

interference refers to the phenomenon that light and dark stripes appear after two light waves meet and interact with each other. When two light waves meet, they will interfere with each other, and the result of interference will depend on their phase difference. If the phase difference is an integer multiple of the wavelength, the two light waves will strengthen each other and form bright stripes; If the phase difference is an odd multiple of half wavelength, the two light waves will cancel each other and form dark stripes.

in holography, the light reflected or transmitted by an object interferes with the reference light to form a hologram. The original object can be reproduced by illuminating this hologram with a certain angle of light. This is because when this light shines on the hologram, it will interfere with the reference light and produce interference fringes, and the shape and position of these fringes are one-to-one corresponding to the original shape and position of the object. By decoding these stripes, the original object can be reproduced. In this process, the principle of light interference plays a vital role.