Technical application of hologram

In photography, this is a brand-new technology. Because hologram has a realistic stereoscopic effect, it has a unique effect of replacing ordinary photos. In foreign countries, some people have made book inserts, trademarks and three-dimensional advertisements with holographic photos; Museums use it instead of displaying precious cultural relics. When a foreign machine tool manufacturing company went to another country to hold a product introduction meeting, it held a machine tool exhibition with holograms instead of objects. The exhibition hall is covered with holograms of various machine tools. These holograms look no different from real machine tools, but they are more interesting to visitors.

A well-conceived hologram is also a beautiful work of art. The United States, France and other countries have holographic photo museums, which collect the most beautiful works in the world.

Holography can also record precious historical relics. In case the cultural relics are seriously damaged, even if nothing is left, we can still reconstruct them according to holography. For example, places of interest such as the Yuanmingyuan in Beijing were burned down by the British and French allied forces that year. Although reconstruction is planned, it is difficult to fully recover because we don't know the whole picture. If holography was invented more than 100 years ago, things would be simple. Inspired by holographic photos of three-dimensional scenes, scientists thought of holographic movies and holographic television. Experimental holographic stereoscopic films have appeared in the former Soviet Union. When this kind of film is shown, what the audience sees is not on the screen, but among the audience, giving people a real feeling of being there. As for holographic TV, it is still under study because of its complex technical problems. 1982, the stereoscopic TV broadcast by German TV station is not laser holographic TV. Its principle is the same as that of ordinary three-dimensional movies, and a pair of special glasses should be worn when watching. It is predicted that by the end of this century, movies and television will be replaced again; At that time, people's cultural and entertainment life may become more colorful because of the emergence of laser panoramic stereo movies and laser stereo TV.

Another important application of holography is to make holographic optical elements, which can replace glass in some special occasions. This special optical element has the advantages of convenient processing, small volume, light weight and thinness. The concave lens can make the beam diverge, and the parallel beam becomes a spherical wave; The hologram shot with small particles mentioned above will also turn the parallel light reference beam into a spherical wave; Such a hologram is also a special concave lens. Optical elements such as convex lens and cylindrical lens can be made in a similar way. This assembly is as thin and light as paper and won't break. At present, telescopes made of holographic optical elements are almost as thick as ordinary myopia lenses. It is also reported that glass windows are made of holographic optical elements. This strange window glass will not affect people's sight, but it can reflect a lot of sunlight and act as a curtain; More interestingly, it can concentrate the sunlight reflected by itself on a row of solar cells installed under the window eaves and convert it into electric energy for indoor use, killing two birds with one stone.

Holographic technology has the ability to see through everything. Because the hologram can accurately reproduce the original, we can use it as a standard to test whether the original has changed; In fact, as long as there is a change in 1 micron, it can be detected by holographic technology. Scientific research and production departments also let laser holography act as an "inspector" of the internal quality of finished products. When checking, add a little pressure or heat to the object being checked; If there are cracks and micropores on an object, its surface will change accordingly. Although the degree of this change is so subtle that the naked eye can't detect it at all, all these flaws and hidden dangers are exposed to the "golden eye" of holography. This method can not only accurately detect the internal quality, but also has the advantage of no damage to the detected object, and is especially suitable for the detection of valuables, such as precious cultural relics and ancient sculptures. Greek scientists used this method to find out the weathering degree of ancient statues. In production, this method is used to check the internal quality of precision parts, aircraft skin and aircraft tires. Laser holographic "inspector" has been used in foreign aircraft tire factories. This method is also used in biological research, such as studying the deformation of skull under stress, studying the growth rate of mushrooms and so on. This kind of holography also contains a wealth of information, and it depends entirely on the set and shooting method used in the production, just like adding a password. You can't copy without the original. Therefore, it has become an effective means to prevent counterfeiting. Various holographic signs have appeared on banknotes, credit cards, magnetic cards and diplomatic visas to prevent counterfeiting. In China, many manufacturers use holographic trademarks to prevent people from forging trademarks and deceiving customers.