Word: hologram
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...waves happened to coincide, the waves strengthened one another and produced a bright spot on the film. But if the crests of one wave lined up with the troughs of another, the waves tended to cancel each other out and barely registered on the film. The result was a hologram, a pattern of light and dark spots that while formless to the eye, encoded all the characteristics of the object. When Gabor shined the same single-frequency light through the film, the result was a three-dimensional image of the object...
...figures on a chessboard stand out in remarkable three-dimensional clarity on a two-dimensional "hologram...
...expressed by Fourier transforms, Stroke set up the optical equivalent of an equation. Using laser light, he made two transparencies -one of the blurred photograph of a microscope, the other of a purposely blurred picture of a spot of light shot by the same camera. Then he produced a hologram by projecting laser light through the blurred light-spot transparency onto unexposed film while simultaneously shining a beam split off from the same laser directly onto the film, thus producing the holographic interference patterns...
Having set up the optical equivalents of Fourier transforms, Stroke beamed laser light first through the transparency of the blurred microscope photograph and then through a "dividing" filter that consisted of both the hologram and the transparency of the blurred spot of light; in mathematical terms, he had thus divided one transform by another. Projected onto film the beam produced a crude but noticeably clearer picture of the microscope. Stroke had solved his optical equation...
Holography Handicaps. To pluck a hologram and release its light waves, a laser beam is passed through it. As the laser beam hits the hologram's interference pattern, it is diffracted into light waves that duplicate those that were reflected from the subject. The viewer sees the subject of the picture in three dimensions, apparently suspended behind the hologram at the same distance it was from the sheet of film...