lasers

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ordinary visible light

ordinary visible light is a combination of waves of different frequency and wavelegnth, that are out of phase with eachother

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lasers produce a narrow,intense beam of monochroma

  • what is a laser?

A laser beam is just a special ray of visible light that has a few extra properties to make it special:

  • all the waves in a laser beam are at the same frequency and the same wavelength.... this makes the light monochramatic ( produces one colour)
  • the light waves are all in phase with eachother, producing a intence beam
  • the waves in a laser beam are said to be coherent 
  • lasers have a low divergence- the beam is narrow and stays narrow
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uses of lasers

     uses of lasers:

  • cutting
  • communication
  • surgery
  • dental
  • light shows
  • barcode scanners
  • recording CDs
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CD players use lasers to read digital information

  • The surface of a CD has a pattern of millions of shallow pits cut into it. The areas between the pits are called lands
  • A laser shone onto the CD is reflected from the shiny bottom surface as it spins around in the cd player
  • The beam is reflected from a land and a pit slightly differently
  • This difference can be picked up by a light sensor, these differences in reflected signals can be changed into electrical signals.
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