GITAM, Department of Engineering Physics

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 LASER

LASER is the acronym for Light Amplification by Stimulated Emission of Radiation.

 

Properties of laser light

Monochromaticity

• Laser light is concentrated in a narrow range of wavelengths

  • lasers produce the purest (most MONOCHROMATIC) light available

Coherence

• All the emitted photons bear a constant phase relationship with each other in both time and phase

  • the light is said to be COHERENT

 

Beam divergence

• All photons travel in the same direction

  • the light is contained in a very narrow pencil

    • almost COLLIMATED

  • laser light is low in divergence (usually)

High irradiance

• Because all the light is concentrated into a narrow spatial band

  • light possesses high radiant power per unit area (i.e. high irradiance)

 

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