hologram
[ hol-uh-gram, hoh-luh- ]
/ ˈhɒl əˌgræm, ˈhoʊ lə- /
noun Optics.
a negative produced by exposing a high-resolution photographic plate, without camera or lens, near a subject illuminated by monochromatic, coherent radiation, as from a laser: when it is placed in a beam of coherent light a true three-dimensional image of the subject is formed.
Also called
holograph.
Words nearby hologram
holoendemic,
holoenzyme,
holofernes,
hologamous,
hologonidium,
hologram,
holograph,
holographic,
holographic will,
holography,
hologynic
Example sentences from the Web for hologram
British Dictionary definitions for hologram
hologram
/ (ˈhɒləˌɡræm) /
noun
a photographic record produced by illuminating the object with coherent light (as from a laser) and, without using lenses, exposing a film to light reflected from this object and to a direct beam of coherent light. When interference patterns on the film are illuminated by the coherent light a three-dimensional image is produced
Medical definitions for hologram
hologram
[ hŏl′ə-grăm′, hō′lə- ]
n.
A three-dimensional diffraction pattern of the image of an object made using holography.
Scientific definitions for hologram
hologram
[ hŏl′ə-grăm′, hō′lə- ]
A three-dimensional image of an object made by holography.
A Closer Look
To produce a simple hologram, a beam of coherent, monochromatic light, such as that produced by a laser, is split into two beams. One part, the object or illumination beam, is directed onto the object and reflected onto a high-resolution photographic plate. The other part, the reference beam, is beamed directly onto the photographic plate. The interference pattern of the two light beams is recorded on the plate. When the developed hologram is illuminated from behind (in the same direction as the original reference beam) by a beam of coherent light, it projects a three-dimensional image of the original object in space, shifting in perspective when viewed from different angles. Appropriately enough, the word hologram comes from the Greek words holos, whole, and gramma, message. If a hologram is cut into pieces, each piece projects the entire image, but as if viewed from a smaller subset of angles. The large amount of information contained in holograms makes them harder to forge than two-dimensional images. Many credit cards, CDs, sports memorabilia, and other items include holographic stickers as indicators of authenticity. Holography is used in many fields, including medicine, data storage, architecture, engineering, and the arts.