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What is Holography?

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.

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

Hologram: 

  • ¨Freezes the intricate wave front of light that carries all the visual information of the scene
  • ¨To view a hologram, the wave front is reconstructed
  • ¨View what we would have seen if present at the original scene through the window defined by the hologram
  • ¨Provides depth perception

Hologram Properties:

  • If you look at these holograms from different angles, you see objects from different perspectives, just like you would if you were looking at a real object.
  • They usually just look like sparkly pictures or smears of color.
  • If you cut one in half, each half contains whole views of the entire holographic image.

Hologram Construction:

  • Laser : Red lasers, usually helium-neon (HeNe) lasers, are common in holography
  • Beam splitter: This is a device that uses mirrors and prisms to split one beam of light into two beams.
  • Mirrors: These direct the beams of light to the correct locations.
  • Holographic film: Holographic film can record light at a very high resolution, which is necessary for creating a hologram. It’s a layer of light-sensitive compounds on a transparent surface, like photographic film.

Hologram Working:

Holography Reconstruction:

What is Laser:

Lasers produce monochromatic light — it has one wavelength and one color. Because of the need for coherent interference between the reference and object beams

Hologram:Some Applications:

  1. Authentication.
  2. Virtual Display.

 

Awadhesh Kumar

Jain Software Developers