Laser

A laser is a device that emits <a href="/facts/Light/jeofpMn4">light</a> through a process of <a href="/facts/Optical_amplification/1Fj9Pfes">optical amplification</a> based on the <a href="/facts/Stimulated_emission/75Q1VIvo">stimulated emission</a> of <a href="/facts/Electromagnetic_radiation/Ynx7ujCW">electromagnetic radiation</a>. The word laser originated as an <a href="/facts/Acronym/nlHK7aRt">acronym</a> for light amplification by stimulated emission of radiation. The first laser was built in 1960 by <a href="/facts/Theodore_Maiman/lbykgHqX">Theodore Maiman</a> at <a href="/facts/Hughes_Research_Laboratories/F6DX2866">Hughes Research Laboratories</a>, based on theoretical work by <a href="/facts/Charles_H._Townes/sRWs7U4e">Charles H. Townes</a> and <a href="/facts/Arthur_Leonard_Schawlow/ScTErtNV">Arthur Leonard Schawlow</a> and the optical amplifier patented by <a href="/facts/Gordon_Gould/FV1dXQHy">Gordon Gould</a>.
A laser differs from other sources of light in that it emits light that is <a href="/facts/Coherence_(physics)/NF1Rgdoa">coherent</a>. <a href="/facts/Spatial_coherence/NF1Rgdoa">Spatial coherence</a> allows a laser to be focused to a tight spot, enabling uses such as optical communication, <a href="/facts/Laser_cutting/3cLypxPr">laser cutting</a>, and <a href="/facts/Photolithography/FTHsauvy">lithography</a>. It also allows a laser beam to stay narrow over great distances (<a href="/facts/Collimated_light/lhd2hhPt">collimation</a>), used in <a href="/facts/Laser_pointer/o6cgsoKa">laser pointers</a>, <a href="/facts/Lidar/b9SPUmLM">lidar</a>, and <a href="/facts/Free-space_optical_communication/V3lyvTxk">free-space optical communication</a>. Lasers can also have high <a href="/facts/Temporal_coherence/NF1Rgdoa">temporal coherence</a>, which permits them to emit light with a very narrow <a href="/facts/Frequency_spectrum/q3Rfs7b0">frequency spectrum</a>. Temporal coherence can also be used to produce <a href="/facts/Ultrashort_pulse/V8joGdvF">ultrashort pulses</a> of light with a broad spectrum but durations as short as an <a href="/facts/Attosecond/G1ynD8f9">attosecond</a>.
Lasers are used in <a href="/facts/Fiber-optic_communication/dc6S0Hg5">fiber-optic</a> and free-space optical communications, <a href="/facts/Optical_disc_drive/IM9ugGbU">optical disc drives</a>, <a href="/facts/Laser_printer/fJ2GrUBj">laser printers</a>, <a href="/facts/Barcode_scanner/k6L6FUlY">barcode scanners</a>, semiconductor chip manufacturing (<a href="/facts/Photolithography/FTHsauvy">photolithography</a>, <a href="/facts/Etching/PM0FmoSb">etching</a>), <a href="/facts/Laser_surgery/LJsjmA6t">laser surgery</a> and skin treatments, cutting and <a href="/facts/Laser_welding/lomhBTaP">welding</a> materials, military and <a href="/facts/Law_enforcement/eneRFUdL">law enforcement</a> devices for marking targets and <a href="/facts/Laser_rangefinder/XlejNw9I">measuring range</a> and speed, and in <a href="/facts/Laser_lighting_display/YkI9btKB">laser lighting displays</a> for entertainment. The laser is regarded as one of the greatest inventions of the 20th century.

Laser open-in-new

Laser