What Does Hologram Mean?
A hologram is a recording of light wave interference patterns that can be played back to create a high-resolution image in full color and three dimensions. Unlike the stereoscopic technologies used to create 3-D experiences today, holograms do not require special glasses.
In principle, it is possible to make a hologram for any type of waveform. Because holography can record interference waves for matter, for example, some types of holograms allow people to interact with computer-generated objects as if they were real.
Many researchers believe that the realism holographic projections provide will play an important role in the metaverse. Unlike avatars, which are simply stylized representations of the human form, holograms actually replicate the way humans interpret light in order to perceive the world in three dimensions.
Techopedia Explains Hologram
In 1951 Dr. Dennis Gabor won the Nobel Prize for inventing and developing the holographic method after he discovered a way to produce images that had the illusion of depth. Dr. Gabor's method was based on his observations about the interaction between light waves (interference) and how light waves align in phase with one another (coherence).
Although, Gabor figured out how to record the interference pattern between a coherent electron beam (object wave) and a coherent background (reference wave) on a photographic plate, conventional light sources at the time provided either too little light or light that was too diffuse. Holography did not become a commercial technology until after 1960's, when lasers capable of amplifying light wave intensity became available.
Since then, various types of holograms have been developed. One type is called a transmission hologram. Transmission holograms are viewed by shining a light through them and looking at the reconstructed image from the side opposite the source. This type of hologram is produced by splitting a laser light into both an illumination beam and a reference beam. The illumination beam is projected directly on the object, while the reference beam is projected directly onto the storage medium to recording light wave interference patterns on film. When played back, the reproduction appears to have depth.
Rainbow holograms are commonly used on credit cards as a security feature. This type of hologram can be viewed in white light and the color is controlled by geometry rather than chemistry. Rainbow holograms are created by using a vertical slit to reduce spectral blur and preserve the hologram's appearance of three-dimensionality. This type of hologram can be viewed in white light and the color is controlled by geometry rather than chemistry.