Holography is different from photography. To begin with, under suitable luminiation, images of holograms are three-dimensional, and so are the objects. Another difference is that photography only records changes of light intensity on the surface of objects, also known as amplitude of the light waves; while holography records all the information of light waves, not only amplitude, but also the phase of light waves. That is to say, it stores and records all the information of light wave field of space objects. Since holograms diffract monochromatic illumination light with particular wavelength, so it could present the original scenes. By “revitalizing” those “frozen” scenes and objects, holography brings them in front of our eyes.endprint