Term: Q-switched laser
https://doi.org/10.1351/goldbook.Q04967

Definition:
A laser in which the state of the device introducing important losses in the resonant cavity and preventing lasing operation is suddenly switched to a state where the device introduces very low losses. This increases rapidly the Quality factor of the cavity, allowing the build-up of a short and very intense laser pulse. Typical pulse durations are in the ns range. The Q-switching may be active (a rotating mirror or electro-optic device) or passive (a saturable absorber).

Related Terms:
1) free-running laser (http://doi.org/10.1351/goldbook.F02521).
2) laser (http://doi.org/10.1351/goldbook.L03459).
3) lasing (http://doi.org/10.1351/goldbook.L03479).
4) absorber (http://doi.org/10.1351/goldbook.A00034).

Source: PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2266 (https://doi.org/10.1351/pac199668122223)

Citation: 'Q-switched laser' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.Q04967

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