How is holography really a thing?

Holography is a technology that utilizes the principles of interference and diffraction to record and reproduce a true three-dimensional image of an object. The first step is to use the principle of interference to record the object light wave information, this is the shooting process, the object to be photographed in the laser irradiation to form a diffuse object beam. Another part of the laser beam as a reference beam to the holographic film, and the object beam superimposed on the interference, the object light wave on the phase and amplitude of each point into the intensity of the spatial variation, thus using the interference fringe contrast and spacing will be the object of the light wave of the whole information recorded. Recorded interference fringes of the negative after developing, fixing and other processing procedures, it becomes a hologram, or holographic photographs, the second step is to use the principle of diffraction to reproduce the object's light wave information, which is the process of imaging, holograms as if a complex grating, in the coherent laser irradiation, a linear record of sinusoidal holograms of the diffracted light waves can generally give two elephants, that is, the original image is also known as the initial image and the * * * yoke image. The reproduced image has a strong sense of three-dimensionality and has a realistic visual effect. Each part of the hologram is recorded on the object of each point of light information, so in principle, each part of it can reproduce the whole image of the original object, through multiple exposures can also be recorded on the same piece of film a number of different images, and can not interfere with each other to show out separately. The first step in holographic technology is to use the principle of interference to record the object light wave information, that is, the shooting process: the object to be photographed in the laser irradiation to form a diffuse object beam; the other part of the laser beam as a reference beam to the holographic negative, and the object beam superposition to produce interference, the object light wave on the phase and amplitude of the points converted into a spatial variation of the intensity, so as to utilize the interference fringes of the contrast between the intervals will be the object of the wave of light The contrast and intervals between the interference fringes are used to record all the information about the object's light wave. Recorded interference fringes of the negative after developing, fixing and other processing procedures, it becomes a hologram, or holographic photographs; the second step is to use the principle of diffraction to reproduce the object's light wave information, which is the process of imaging, holograms as if a complex grating, in the coherent laser irradiation, a linear record of sinusoidal hologram diffraction of the light waves can generally give two elephants, that is, the original image and **** yoke of elephants.