Large-scale experiment: what problems will laser holography encounter? How to solve it? What color is the holographic image you see?

The most common problem is that in the process of adjusting the light path, the light intensity of the object light and the light intensity of the reference light are difficult to reach about 1: 4. At this time, it is necessary to adjust the angle between the object light and the reference light, preferably less than 30 degrees, and at the same time weaken the intensity of the reference light, and move the beam expander of the reference light away from the dry plate. Secondly, the problem is the optical path difference. It is best to ensure that the optical path difference between the object light and the reference light is less than 2cm. It's easy to have nothing on film, which is very common when shooting for the first time. In short, it is enough to ensure that there is no vibration and no one to talk during shooting, and the exposure time is long enough, the development time is appropriate, and the fixing time is sufficient.

The color of holographic image is the color of reference light, generally red and green.

This is the phenomenon I photographed. The effect is not very good, but it is still obvious.