What are the applications of holographic technology?

The principle of holography is applicable to all kinds of waves, such as X-rays, microwaves, sound waves and electronic waves. As long as these fluctuations have sufficient coherence in forming the interference pattern. Optical holography is expected to be widely used in three-dimensional movies, televisions, exhibitions, microscopes, interferometry, projection lithography, military reconnaissance and surveillance, underwater detection, internal detection of metals, preservation of precious historical relics, works of art, information storage, remote sensing, research and recording of transient phenomena and transient processes (such as explosion and combustion) with extremely rapid changes in physical state.

In life, we can often see the application of holographic technology. For example, on some credit cards and paper money, the Russian physicist Yuri was used. The full-color holographic image technology invented by Danny Sook in 1960s produced a "rainbow" holographic image on polyester film. However, these holographic images are only used as a complex printing technology to achieve the purpose of anti-counterfeiting. Their sensitivity is low, their colors are not realistic enough, and they are far from the real state. The researchers also tried to use dichromate glue as emulsion to make holographic recognition equipment. Some fighters are equipped with this kind of equipment, which enables pilots to concentrate on the enemy. When some precious cultural relics are photographed by this technology, they can be truly reproduced in three dimensions for visitors to enjoy, while the original objects are properly preserved to prevent theft. Large holograms can not only display cars, satellites and various three-dimensional advertisements, but also copy portraits and wedding commemorative photos with pulse holography. Small holograms can be worn around the neck to form beautiful decorations, which can reproduce people's favorite animals, colorful flowers and butterflies. The rapid development of embossed rainbow holograms can not only become lifelike cartoons, greeting cards and three-dimensional stamps, but also appear as anti-counterfeiting marks on trademarks, ID cards, bank credit cards and even banknotes. Holographic stereo photo decorated on books and holographic rainbow shining on gift packaging make people realize the new leap of printing technology and packaging technology in 2 1 century. Molded holographic logo, because of its three-dimensional layering, rainbow effect changing with observation angle, ever-changing anti-counterfeiting logo, and the close combination with other high-tech anti-counterfeiting means, has pushed the anti-counterfeiting technology in the new century to a new brilliant peak.

In addition to optical holography, infrared, microwave and ultrasonic holography technologies have been developed, which are of great significance in military reconnaissance and surveillance. As we know, the general radar can only detect the direction and distance of the target, while holography can give three-dimensional images of the target, which plays a great role in identifying aircraft and ships in time. Therefore, people attach great importance to it. However, due to the rapid attenuation of visible light in the atmosphere or water, it can't even work in bad weather. In order to overcome this difficulty, infrared, microwave and ultrasonic holographic techniques have been developed, that is, coherent infrared, microwave and ultrasonic holographic photographs are taken, and then the object images are reproduced by visible light. This holographic technology has the same principle as the ordinary holographic technology. The key of technology is to find sensitive recording media and suitable copying methods.

Ultrasonic holography can reproduce the three-dimensional pattern of underwater objects, so it can be used for underwater reconnaissance and surveillance. Because objects that are opaque to visible light are often transparent to ultrasonic waves, ultrasonic holography can be used in underwater military operations, medical perspective and industrial nondestructive testing.

In addition to using light waves to generate holograms, it has also developed into using computers to generate holograms. Holograms are widely used and can be made into various thin film optical elements, such as various lenses, gratings, filters, etc. , can overlap in space, very small and light, suitable for space flight. Using hologram to store data has the advantages of large capacity, easy extraction and pollution prevention.

The method of holography has expanded from the optical field to other fields. Such as microwave holography and acoustic holography, have been greatly developed and successfully applied to industrial medical care. Holography of seismic waves, electronic waves and X-rays is also under in-depth study. Holograms are widely used. Such as shock wave used to study rocket flight, nondestructive testing of honeycomb structure of aircraft wing, etc. Now there are not only laser holography, but also white light holography, rainbow holography and panoramic rainbow holography, so that people can see all sides of the scene. Holographic three-dimensional display is developing towards holographic color stereoscopic TV and movies.