How is the principle of holography put forward?

The principle of holography was put forward by the Hungarian-born British scientist Dennis Gaby (1900 ~ 1979) in 1947. At that time, he was studying how to overcome the resolution limit of the electron microscope (at that time, it was 1.2 nm), and he proposed a holographic theory that could record all the information of light intensity and phase, so as to obtain a three-dimensional image of the object (he only talked about coaxial type). In addition, he actually got the first holographic picture of human beings, but it was very vague.

At that time, it was thought that holographic photography needed monochromatic strong light with good coherence, and obviously only lasers were qualified. Therefore, it was not until 1960 laser appeared that holography became a practical technology. Visible holography is the most interesting application of laser.