Two-beam, wide-viewing angle holographic apparatus

Claim 1

A holographic apparatus for recording holograms in transmission of a relatively large object and providing a wideviewing angle as well as both temporal and spatial coherence matching, said apparatus comprising: a. a solid-state laser for developing a coherent, substantially monochromatic and collimated first light beam having a relatively limited coherence length, said collimated first light beam extending along a first path; b. a first mirror oriented to redirect said first beam along a second path substantially perpendicular with respect to said first path; c. a beam splitter disposed in the path of said redirected first beam and oriented to reflect a portion of said first beam along a third path to provide a reference beam, said beam splitter transmitting the remaining major portion of said first beam along said second path to provide a scene beam; d. a second, third and fourth mirror for redirecting said scene beam, first in a direction perpendicular to both said first path and said second path, second in a direction parallel to said second path, and third in a direction parallel to said first path; e. a beam bender for redirecting said scene beam along a path defining a main axis and perpendicular to both said first and said second path, and toward a photosensitive material on which the hologram is to be recorded, said beam bender maintaining the path lengths of the individual rays of said scene beam substantially constant throughout its cross section; f. a light diffuser interposed in the path of said scene beam along said main axis and ahead of the object to be recorded; g. a fifth and a sixth mirror for further redirecting said reference beam, first into a direction parallel to said main axis, and then toward the plane of the photosensitive material; h. a planar photosensitive material disposed in said plane for recording the hologram; and i. condensing lens means interposed between said light diffuser and the object for collecting the light scattered by said light diffuser and directing and focusing it through the object onto said photosensitive material, said beam bender, said fourth mirror, and said fifth and said sixth mirror being so arranged that the angle between said scene beam and said reference beam, where they intersect at said photosensitive material, is between approximately 60* and approximately 90*.