Traditional optical holography

Holographic image technology: a technology to record and restore the three-dimensional image of the real pattern of an object by using the principles of interference and diffraction. It began to appear in the late 1940s and gradually improved in the 1990s.

Holography? Is it? All information? Record and restore all the information of the object with projection. This technology is also called virtual imaging technology and holographic imaging. The principle is to record the phase and amplitude of light wave completely through light wave interference, and display the light wave information emitted by the object through diffraction, so as to realize imaging.

1947, Gabor put forward the imaging concept of holographic imaging technology in the study of electron microscope. Imaging is to use the principle of optical interference to record specific light waves in the form of objects and reproduce them to form a three-dimensional image. The image records the amplitude, phase and brightness of the object, so it is called holography and contains all the information. At that time, the imaging quality was very poor, and it was recorded with a mercury lamp. Because the performance of mercury lamp is too poor to separate coaxial holographic diffraction waves, it took scientists about ten years to greatly improve holographic imaging technology. Holography has made great progress since the appearance of laser in the 1960s.

On the basis of 1962, will Les and apatinib? Side-looking radar applied this theory, and a brand-new off-axis holographic technology was invented, and holographic technology entered the development stage. This technology uses special off-axis light to record holographic images, and then uses reconstructed light to obtain diffraction components and observe the images, thus overcoming the problem of poor imaging quality.

1969, Benton invented rainbow holography, and observed imaging under incandescent lamp. Add a slit with width at a proper position to limit light waves and reduce color blur. According to the characteristics of human eyes, vertical information is sacrificed, and horizontal information is retained, thus reducing the requirements for light sources. With the invention of this technology, holography entered the third stage.

The traditional holographic technology uses silver halide to make photosensitive film, and completes the post-processing of image and fixing. The production process is very complicated and needs to be developed and locked. Modern holographic technology uses photosensitive media, photoconductive plastics, photorefractive crystals and other materials, which saves post-processing steps and has high information capacity and diffraction rate.