Holography is a new photography technology that records all the information in the reflected or transmitted light waves of the object. Ordinary photography uses the principle of lens imaging to record on the photosensitive film the changes in light intensity on the surface of the object. Surface like.

Holography records the intensity of the reflected light wave from the object, and also records the phase of the reflected light wave. The above purpose can be achieved by superimposing a reference beam and a reflected beam on the photosensitive film to produce an interference pattern.

Holography is a photographic record that uses a set of auxiliary reference beams to express a three-dimensional effect.

Light wave is a kind of electromagnetic wave, which carries amplitude and phase information during propagation. Ordinary photography uses photosensitive materials (such as photographic films) as recording media, and uses lens imaging systems (such as cameras) to image objects on the photosensitive materials. What it records is only the intensity distribution image of the light wave from the object, that is, the amplitude information, but does not include the phase information. Therefore, ordinary photography can only capture two-dimensional (planar) images. In order to simultaneously record the amplitude and phase information of light waves, a coherent reference light can be used, and the optical path difference between the object light and the reference light can be used to determine the phase difference between the two light waves. Therefore, with the help of reference light, the amplitude and phase information of the light wave from the object can be recorded.

References Baidu Encyclopedia Holographic Photography