The research and development background of holographic imaging technology

In 1947, the Hungarian Dennis Gabor proposed a new imaging concept called holography while studying electron microscopes. The imaging of holography uses the principle of light interference to record the specific light waves emitted by the object in the form of articles and reproduce them under special conditions to form a realistic three-dimensional image. This image records the amplitude, phase, brightness, and Shape distribution and other information, so it is called holography, which means it contains all information. However, under the conditions at that time, the imaging quality of holographic images was very poor. Only mercury lamps were used to record holographic information. However, because the performance of mercury lamps was too poor to separate coaxial holographic diffracted waves, a large number of scientists spent ten years without success. This technology has made great progress.

Holography has developed rapidly since the advent of lasers in the 1960s.

In 1962, Americans Reis and Apatniks applied the "side-looking radar" theory in the communications industry to holography based on basic holography, and invented off-axis holography technology. , driving holographic technology into a new stage of development. This technology uses off-axis light to record the holographic image, and then uses the off-axis reproduced light to obtain three spatially separated diffraction components. The required image can be clearly observed, effectively overcoming the problem of poor hologram imaging quality.

In 1969, Benton invented rainbow holography, which can observe bright three-dimensional images under incandescent light. Its basic feature is to add a slit of a certain width at an appropriate position to limit the reproduced light waves to reduce the color blur of the image. According to the horizontal arrangement characteristics of the human eye, the vertical object information is sacrificed while the horizontal object information is retained, thereby reducing the blurring of the image. Light source requirements. The invention of rainbow holography has brought holography into the third stage of development. Traditional holographic technology uses materials such as silver halide to make photosensitive film to complete holographic image information.

Post-processing such as fixing, the entire production process is very tedious to record, due to the need for development and cumbersome processes. Modern holographic technology materials use new photosensitive media, such as photothermal plastics, photorefractive crystals, photopolymers, etc., which not only eliminate the post-processing steps in traditional technologies, but also have higher information capacity and diffraction rate than traditional materials. higher.

However, using photosensitive film or new photosensitive media requires reproducing the recorded wavefront information through light wave diffraction, and directly observing the reproduction results with the naked eye. This makes it difficult to quantitatively analyze the accuracy of the image and form an accurate hologram. image.

In the late 1960s, Goodman, Lawrence and others proposed a new holographic concept—digital holographic technology, ushering in the era of precise holographic technology.

In 1971, Dennis Gable won the Nobel Prize for his invention of holography.

After the 1980s, laser holography technology developed rapidly and became a new high-tech industry that suddenly emerged. Among laser holographic technologies, holographic display technology has attracted much attention because it is closer to people's daily lives. Since white light reproduction holography technology can view three-dimensional images of objects in the daytime natural environment or under ordinary white light illumination conditions, we have been studying the latest development and application of holographic technology, and we look forward to our own efforts to achieve rapid development of holographic display technology.

In the 1990s, with the emergence of high-resolution CCDs, people began to use CCD and other photosensitive electronic components to replace traditional photosensitive films or new photosensitive media to record holograms, and use computers to simulate optical diffraction digitally. To present images, the recording and reproduction of holograms are truly digital.