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Laser

For other uses, see Laser (disambiguation).
"Laser beam" redirects here. Not to be confused with LazarBeam or Lazer Beam.

A telescope emitting four orange laser beams.
A telescope in the Very Large Telescope system producing four orange laser guide stars

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word laser is an anacronym that originated as an acronym for light amplification by stimulated emission of radiation.[1][2] The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow.[3]

A laser differs from other sources of light in that it emits light that is coherent. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. It also allows a laser beam to stay narrow over great distances (collimation), a feature used in applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which permits them to emit light with a very narrow frequency spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of light with a broad spectrum but durations as short as a femtosecond.

Lasers are used in optical disc drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic, and free-space optical communication, semiconducting chip manufacturing (photolithography), laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for marking targets and measuring range and speed, and in laser lighting displays for entertainment. Semiconductor lasers in the blue to near-UV have also been used in place of light-emitting diodes (LEDs) to excite fluorescence as a white light source; this permits a much smaller emitting area due to the much greater radiance of a laser and avoids the droop suffered by LEDs; such devices are already used in some car headlamps.[4][5][6][7]

  1. ^ Taylor, Nick (2000). Laser: The Inventor, The Nobel Laureate, and The Thirty-Year Patent War. Simon & Schuster. p. 66. ISBN 978-0684835150.
  2. ^ Ross T., Adam; Becker G., Daniel (2001). Proceedings of Laser Surgery: Advanced Characterization, Therapeutics, and Systems. SPIE. p. 396. ISBN 978-0-8194-3922-2.
  3. ^ "December 1958: Invention of the Laser". aps.org. Archived from the original on December 10, 2021. Retrieved January 27, 2022.
  4. ^ "Semiconductor Sources: Laser plus phosphor emits white light without droop". November 7, 2013. Archived from the original on June 13, 2016. Retrieved February 4, 2019.
  5. ^ "Laser Lighting: White-light lasers challenge LEDs in directional lighting applications". February 22, 2017. Archived from the original on February 7, 2019. Retrieved February 4, 2019.
  6. ^ "How Laser-powered Headlights Work". November 7, 2011. Archived from the original on November 16, 2011. Retrieved February 4, 2019.
  7. ^ "Laser light for headlights: Latest trend in car lighting | OSRAM Automotive". Archived from the original on February 7, 2019. Retrieved February 4, 2019.