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Laser components: cutaway view
Laser components: cutaway view Basic laser components.

laser

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Also known as: light amplification by stimulated emission of radiation(Show More)
Written by
Jeff Hecht
Science and technology writer. Author of City of Light: The Story of Fiber Optics.
Jeff Hecht
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Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
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“Purifying” photons: Scientists found a way to clean light itself • Dec. 23, 2025, 3:46 AM ET (ScienceDaily)
Physicists made atoms behave like a quantum circuit • Dec. 22, 2025, 10:15 PM ET (ScienceDaily)

laser, a device that stimulates atoms or molecules to emit light at particular wavelengths and amplifies that light, typically producing a very narrow beam of radiation. The emission generally covers an extremely limited range of visible, infrared, or ultraviolet wavelengths. Many different types of lasers have been developed, with highly varied characteristics. Laser is an acronym for “light amplification by the stimulated emission of radiation.”