What is Holography?
In Official Blog, Programming, Tech-BLOG, Tech-Forum, TechnicalHistory 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:
- Authentication.
- Virtual Display.
Awadhesh Kumar