What are the necessary conditions to reproduce the same virtual image as the original in holography?

Holography is based on the interference principle of light, so it requires that the light source must have good coherence, and the light and the light illuminating the object are separated from the same laser beam. The appearance of laser provides an ideal light source for holography. This is because laser has good spatial and temporal coherence. In the experiment, a good hologram can be obtained by shooting small diffuse objects with He-Ne laser.

Holograms do not directly display images of objects. When the laser beam or monochromatic light is incident in the direction close to the reference light, the image of the original object can be observed at an appropriate angle. This is because the laser beam diffracts on the interference fringes of the hologram and reproduces the original light wave. The reconstructed image is stereoscopic.

Extended data:

The salient features and advantages of holography are as follows:

1. The reconstructed stereoscopic image is beneficial to the preservation and collection of precious artworks.

2. When shooting, every point is recorded on any point of the hologram. Once the photo is damaged, it doesn't matter much.

3. Holograms have strong stereoscopic impression and vivid images, and can be displayed in various exhibitions with the help of lasers, which will get very good results. ?

Baidu encyclopedia-holographic photography