laser

Introduction
History
Fundamental principles
- Energy levels and stimulated emissions
- Laser elements
- Laser beam characteristics
Types of lasers
Laser applications
- Transmission and processing of information
  - Laser scanners
  - Optical discs
  - Fibre-optic communication systems
- Precise delivery of energy
  - Industrial uses
  - Medical applications
  - High-energy lasers
- Alignment, measurement, and imaging
  - Surveying
  - Interferometry and holography
  - Research tool

References & Edit History Quick Facts & Related Topics

Images & Videos

Using lasers to detect structural damage in metal objects

At a Glance

laser summary

Quizzes

Yellow transportation sign with ASAP (as soon as possible) on violet color sky background. (acronyms)

Figure Out the Acronyms ASAP Vocabulary Quiz

Related Questions

How are carbon-dioxide lasers used to remove or cut tissue during surgery?
How are lasers used for alignment and surveying?
How can very short laser pulses help scientists study chemical reactions?
How did Albert Einstein’s 1916 idea help lead to the development of lasers?
How did Charles H. Townes create the first working maser?
How did Gordon Gould eventually win laser patents?
How did laser scanners change supermarket checkout systems?
How did lasers help create the first three-dimensional holograms?
How do Blu-ray discs store more data than DVDs?
How do dopants help crystal and glass lasers produce light?
How do pulsed lasers remove tattoos and treat port-wine stains?
How do vertical-cavity surface-emitting lasers differ from edge-emitting semiconductor lasers?
How does a continuous-wave laser differ from a pulsed laser?
How does a helium-neon laser produce a red beam?
How does diffraction affect the width of a laser beam?
How does stimulated emission produce more light in a laser?
How is a population inversion created in a laser material?
What colour of light did Theodore Maiman’s ruby laser produce?
What colours can helium-neon lasers emit?
What do the letters in the acronym laser represent?
What happens to an atom when it absorbs energy and enters an excited state?
What materials can serve as laser media?
When did Theodore Maiman produce the first laser beam?
Which gases were used in the first gas laser at Bell Labs?
Who built the first gas laser?
Who built the first working laser?
Who coined the word laser?
Who first observed stimulated emission in 1928?
Why can pulsed lasers produce extremely high peak power?
Why did Charles H. Townes, Aleksandr Prokhorov, and Nikolay Basov receive the 1964 Nobel Prize in Physics?
Why did Gordon Gould and Charles Townes disagree over laser patents?
Why do DVDs use red lasers instead of the infrared lasers used in audio CDs?
Why is a population inversion necessary for laser action?
Why was synthetic ruby used in the first working laser?
Why were helium-neon lasers among the first lasers used widely in business?
Is mathematics a physical science?
When did science begin?
Where was science invented?

Technology Engineering Mechanical Engineering

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External Websites

APS Physics - December 1958: Invention of the Laser
American Society of Mechanical Engineers - 7 Top Applications of Lasers in Manufacturing
National Center for Biotechnology Information - Laser Complications
Lawrence Livermore National Laboratory - National Ignition Facility and Photon Science - NIF's Guide to How Lasers Work
University of Central Florida Pressbooks - University Physics Volume 3 - Lasers

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

laser - Children's Encyclopedia (Ages 8-11)
laser and maser - Student Encyclopedia (Ages 11 and up)

laser

instrument

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

Fact-checked by

Britannica Editors

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....

Britannica Editors

Last updated

Oct. 30, 2026 •History

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.”

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