holography in laser<\/p>\n\n\n\n
Holography is a technique to record and reconstruct a three-dimensional scene on a two-dimensional plane (hologram) based on optical diffraction and interference.<\/p>\n\n\n\n
There are three types of holograms:<\/p>\n\n\n\n
Reflection hologram.
Transmission hologram.
Hybrid hologram.<\/p>\n\n\n\n
The photographic recording of the image is called a hologram, which appears to be an unrecognizable pattern of stripes and whorls but which\u2014when illuminated by coherent light, as by a laser beam\u2014organizes the light into a three-dimensional representation of the original object.<\/p>\n\n\n\n
<\/p>\n\n\n\n
<\/p>\n\n\n\n
Today, different laser wavelengths are used to create holograms. The holography can be in different wavelengths lasers . Originally, HeNe lasers with a wavelength of 633 nm or various wavelengths from Argon\/Krypton ion lasers were used as light source.<\/p>\n\n\n\n
The holography can be in regular lights. However if a Laser source is used instead, then the three emerging beams will be in different directions. This is called ‘Off-Line Holography’. Holography in laser allows us to observe one kind of beam at a time. This is the reason that a laser is needed in holography.<\/p>\n\n\n\n
To record display holograms one of the beam serves as a reference beam where the other beam illuminates a three-dimensional object. Both beams are then combined forming a pattern in a photosensitive medium. To record the hologram the holographic pattern has to be illuminated, usually also with a laser source.<\/p>\n\n\n\n