P3D Re: Final thread: Holograms reconsidered

[KenDunkley@xxxxxxx]

I had second thoughts following my last correspondence and realized that there
was indeed a way to recover "most" of the information lost when "certain"
image plane holograms are cut in half.   The information regeneration scheme I
will describe should work readily with transmission image plane holograms. 

Beginning with only one half of the cut image plane hologram which
reconstructs only one half of its image, illuminate the hologram with its
conjugate beam.  The conjugate laser beam is identical to the reference beam
except it is propagating in the opposite direction.   This will produce a real
pseudoscopic image of the lens (which originally projected the image of the
object onto the plane of the hologram during the recording porcess) and the
object itself.   

However, this real pseudoscopic image of the lens and the object is difficult
to observe because it cannot be seen in its entirety.  Typically this image
will project 2 to 3 feet from the (rear face of the) hologram and only small
segments can be seen from any fixed position.  Since the image is being
projected from the broken hologram this hologram always appears in the
background.  You can't see this (real pseudoscopic) image in its entirity at
the same time but you can move your eyes to see portions of it at different
times.    

Finally, the majority of the original image can be recovered by making an
image plane hologram of the real pseudoscopic image of the object.  

With this done, one need only illuminate this new hologram with  its conjugate
beam.  The result will be a tranmission image plane hologram of the original
object fully reconstructed (with both halves visible) except that the viewing
angle will be only about 1/3 that of the original.  A reduced viewing angle
represents a loss of information similar to the worm hole I alluded to in my
correspondence on Thu, 16 Jul 1998 03:05:45 EDT.

Sorry Bob, I owe you an apology for not realizing this sooner.  

Respectfully submitted

Ken Dunkley



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