Holographic technology has advanced rapidly since the introduction of laser technology, owing to the high coherence of lasers. The maturation of holographic technology is causing projection technology to shift closer to the real 3D world.

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Principles of 3D Technology

(1) Using polarised lenses

It observes the scene with the human eye, then shoots two movie photographs with a slight horizontal parallax using two movie cameras positioned side by side to reflect the person's left and right eyes.

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The audience's left eye can only see the left image while wearing special polarised lenses, while the right eye can only see the right image. The binocular convergence function, which is produced by the brain's nerves, superimposes the left and right images on the retina. Visual effects in three dimensions. This 3D technology is not truly 3-dimensional, and its imaging is still dependent on a two-dimensional projection.

(2) 3D holographic holography

1. The holographic theory

Wavefront interference recording and wavefront diffraction reconstruction are the two stages in holography [7]. Using Fresnel holography as an example, the first step is interference recording of the wavefront, as shown in Figure 1. Figure 1: Fresnel holography recording optical path

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Figure 1: Holography optical path recording

The laser beam passes through the shutter and is split into two beams by the beam splitter, as shown in the diagram: the transmitted beam is mirrored by the plane mirror M2, and the beam enlarged by the beam expander L2 is projected as the reference light onto the holographic dry plate E.

The light beam passes through the centre of each element, and the optical axis of the entire optical path is on the same horizontal plane. The object light and the reference light form a 45-degree angle.

After standing for one minute, clamp the holographic dry plate on the dry plate rack in the dark, align the photosensitive emulsion with the object light and reference light, and start the time exposure system. The hologram is created by removing the dry plate, developing it in a dark space, washing it with water after it has been fixed for a period of time, rinsing it with water, and finally drying it.

The third stage of holography growth is from the 1980s to the present. Reflection holography, image holography, rainbow holography, embossing holography, and synthetic holography are examples of laser recording and white light reproduction at this level.

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YNDenisyuk, a scientist from the former Soviet Union, proposed a white light reflection hologram based on G.Lippmann's standing wave natural colour photography process in 1962. Since then, applied science has progressed, and many scientists have begun their own investigations into the application potential of holography and related fields like holographic interferometry, holographic storage, and holographic optics.

The invention of SABenton rainbow holography during this time period paved the way for the use of show holograms. Gabor's holographic concept won the Nobel Prize in Physics in 1971 as a result of their success.

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