In the movie, there are some fairly impressive displays of holography. In reality, holography is quite possible, although not to show generated images. Holograms are made by shining a laser through a beam splitter and directing one beam directly to the film and the other beam to the object of which a hologram should be made, and then to the holographic film, as shown in the picture at left. According to HowStuffWorks, the process is as follows:
- The laser points at the beam splitter, which divides the beam of light into two parts.
- Mirrors direct the paths of these two beams so that they hit their intended targets.
- Each of the two beams passes through a diverging lens and becomes a wide swath of light rather than a narrow beam.
- One beam, the object beam, reflects off of the object and onto the photographic emulsion.
- The other beam, the reference beam, hits the emulsion without reflecting off of anything other than a mirror.
When the hologram is to be displayed, it is then necessary to make another setup. Shining a monochrome light at the film makes the object appear in the same spot relative to the film where the object was initially. In theory, it would be possible to construct holographs from raw light, but this technology is not fully developed.
. Tracy Wilson. “How Holograms Work.” HowStuffWorks, 2007. http://science.howstuffworks.com/hologram.htm, September 21, 2014.