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“Laser” is an acronym for light amplification by stimulated emission of radiation, related to the earlier “maser” concept for microwave frequencies.
Laser terminology covers the vocabulary used to describe how lasers work and how different laser devices are classified. The word “laser” originated as an acronym for “light amplification by stimulated emission of radiation.” The related earlier device is the “maser” (microwave amplification by stimulated emission of radiation), and devices operating at microwave or lower radio frequencies are generally called masers, while higher-frequency devices are called lasers. In practice, the field also uses verbs such as “to lase” (to give off coherent light) and “lasing” (when a laser is operating). The terms laser and maser are also used for naturally occurring coherent emissions, such as astrophysical masers and atom lasers. Key related concepts include coherence (spatial and temporal), which distinguishes laser light from incoherent sources and enables tight focusing, narrow beams over distance, and narrow frequency spectra. Fundamental processes use “stimulated emission,” where an incoming photon triggers an excited atom or molecule to emit an identical photon (matching wavelength, phase, and polarization), enabling amplification and a chain reaction when many particles are in suitable excited states (often described via “population inversion” and an “active laser medium”). Laser design terminology commonly refers to the “gain medium,” “pumping” (energy supplied to excite the medium), and “optical cavity” or “resonator” (feedback elements such as mirrors), along with the “output coupler” and the “lasing threshold” (minimum pump power needed for laser action).
“Laser” is an acronym for light amplification by stimulated emission of radiation, related to the earlier “maser” concept for microwave frequencies.
Core terminology includes coherence (spatial/temporal), stimulated emission, population inversion, gain medium, pumping, optical cavity/resonator, and lasing threshold.
Laser light is produced by stimulated emission within a feedback system (resonator), which selects and amplifies specific wavelengths and modes to create coherent output.
A device that emits light through optical amplification based on stimulated emission of electromagnetic radiation.
A device that performs microwave amplification by stimulated emission of radiation.
A process where an incoming photon triggers an excited atom or molecule to emit a second photon identical in wavelength, phase, and polarization.
A property of laser light describing correlated phase relationships, including spatial (beam quality) and temporal (narrow frequency/phase correlation) coherence.
A condition where more particles occupy an excited energy state than a lower state, enabling net amplification via stimulated emission.
The material in a laser that amplifies light through stimulated emission after being excited by pumping.
Supplying energy to the gain medium (e.g., via electric current or light) to create the excited states needed for lasing.
A feedback structure (typically mirrors) that causes light to pass repeatedly through the gain medium and favors specific resonant modes.
A partially transparent mirror (or equivalent element) that allows some of the circulating laser light to exit as the output beam.
The minimum pump power required for the gain to overcome cavity losses so that laser light is produced.
To give off coherent light, especially referring to the gain medium’s operation when a laser is running.
“Can you explain what "“Laser” is an acronym for light amplification by stimulated emission of radiation, related to the earlier “maser” concept for microwave frequencies." means in simple terms?”