Holographic recording process of holography

In a typical off-axis holographic optical path layout (Figure 1), the beam emitted by the laser is divided into two beams by the beam splitter B, and one beam is directly projected on the holographic negative H (a high-resolution photosensitive material) after being reflected by the mirror M, which is called reference light; Another beam illuminates an object, and the light reflected (or transmitted) by the object is called object light. The interference between the object light and the reference light on the holographic negative constitutes a very complex and fine interference fringe pattern. These interference fringes record the amplitude and phase information of object light and its contrast and position change. Holographic negatives become holograms after conventional development and fixation. The appearance of hologram seems to have nothing to do with the appearance of the original object, but it records all the information of the object light in the form of optical coding.