Term: non-linear optical effect
https://doi.org/10.1351/goldbook.N04197

Definition:
An effect brought about by electromagnetic radiation the magnitude of which is not proportional to the irradiance. Non-linear optical effects of importance to photochemistry are harmonic frequency generation, lasers, Raman shifting, upconversion, and others.

Related Terms:
1) photochemistry (http://doi.org/10.1351/goldbook.P04588).
2) harmonic frequency generation (http://doi.org/10.1351/goldbook.H02744).
3) upconversion (http://doi.org/10.1351/goldbook.U06574).

Source: PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2256 (https://doi.org/10.1351/pac199668122223)

Citation: 'non-linear optical effect' 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.N04197

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