Topics Discussed...
                           1. INTRODUCTION
                           2. Hologram & Holography
                           3. History of holography
                           4. Photography  vs  Holography
                           5. HOLOGRAM- Recording & Reading
                           6. Usages
                           7. Types of hologram
                           8. Holographic Memory
                           9. Holographic Versatile Discs (HVD)
                           10.Applications
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         Hologram & Holography
               A hologram is a flat surface that, under 
                   proper illumination, appears to contain a 
                   three-dimensional image.
                
               Holography  is  the  Nobel  award-winning 
                   science
               The  hologram  presents  a  true  three 
                   dimensional  recreation  of  the  original 
                   object. 
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         History of holography
         Invented in 1948 by Dennis Gabor for 
             use in electron microscopy, before the 
             invention of the laser
         Leith and Upatnieks (1962) applied 
             laser light to holography and introduced 
             an important off-axis technique
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                              Conventional vs. 
                 Holographic photography
          Conventional:
               2-d version of a 3-d scene
               Photograph lacks depth perception  
               Film sensitive only to radiant energy
               Phase relation (i.e. interference) are lost
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                           Conventional vs. 
              Holographic photography
               Hologram:
                    Freezes the intricate wavefront of light that 
                       carries all the visual information of the scene
                    To view a hologram, the wavefront is 
                       reconstructed
                    View what we would have seen if present at 
                       the original scene through the window defined 
                       by the hologram
                    Provides depth perception
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