The New York Times Book of Physics and Astronomy by Dean Cornelia

Author:Dean, Cornelia [Dean, Cornelia]
Language: eng
Format: epub, mobi
Tags: Itzy, Kickass.to
ISBN: 9781402793264
Amazon: 1402793200
Publisher: Sterling
Published: 2013-09-05T04:00:00+00:00

Study of Deformations

Only when the plate is illuminated by a beam passing through that same sheet of ground glass (or its twin), positioned precisely as before, are the light waves unscrambled and the image brought into view.

An application of holography to design problems involves the study of deformations in structures under stress. Before application of the stress, a hologram of the object is made. When developed and illuminated, this generates a three-dimensional image of the object as it was to begin with.

The object, left where it was relative to the hologram, is then squeezed. Wherever its shape is changed, even to a degree unobservable by other means, the light waves of its image clash with those in the hologram.

The battle between light waves from the two images, those of the unstressed device and those from its deformation, produces a series of interference lines visible to the unaided eye. These lines delineate areas of equal deformation (or stress) and can be photographed to guide engineers in their design work.

The presentation of holograms to the public seems to be in the offing. General Motors has on display at its Detroit headquarters a hologram showing a futuristic car. By lowering one’s head, it is possible to look under the image of the car and see beyond.

Small holograms on film can be purchased for home display, but mass production methods are not yet satisfactory. The annual science book, Science Year, published by Field Enterprises, may include a hologram in its 1967 issue, and Life magazine has been exploring the possibility of publication. However, as an editor at Life put it the other day, the problem is “to find something that can be bound into a magazine and makes economic sense.”

This remark is applicable to many current lines of holographic research. The prospects are exciting, but many applications are not yet economical.

—March 19, 1967

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