Use Of A Holographic Lens For Producing Cylindrical Holographic Stereograms

Abstract

The production of cylindrical holographic stereograms, or multiplex holograms, requires the use of a large, low f/number cylindrical lens to form a line image on the holographic film. To have an image of reasonable size for display purposes, the f/number of the lens must be quite small, on the order of f/1, and the dimensions of the lens must be reasonably large, on the order of eight inches in width and height. The optical quality of the lens must also be quite good to prevent interference fringes in the image and to minimize the number of multiple exposures in the multiplexing process. For economic rea-sons, adjustable, oil-filled plastic lenses are commonly used for this purpose instead of conventional optics. Considerable difficulty is usually encountered, however, in adjusting the oil lens to minimize aberrations. Making the oil lens adequately adjustable, while at the same time maintaining the oil seal, also presents mechanical difficUlties. We have eliminated these problems with the use of an off-axis, holographic cylindrical lens. The lens is easy to make, requires no adjustment, and has excellent optical quality. Techniques for producing this lens and its use in making multiplex holograms are described.