Term: downconversion
https://doi.org/10.1351/goldbook.DT07362

Definition:
Process by which a photon with frequency ν1 interacts with a non-linear medium and splits into two simultaneously emitted photons with frequencies ν2 and ν3 so that the energy is conserved: \[\nu _{1}=\nu _{2}+\nu _{3}\]

Notes:
0) Also known as a parametric downconversion.
1) The efficiency of the conversion process depends on the parametric gain in the non-linear material. This in turn depends on the @P04792@ of the incident radiation, the photon frequencies, their indices of refraction in the material, and the non-linear 'hyper-susceptibility' of the material.

Related Terms:
1) power (http://doi.org/10.1351/goldbook.P04792).
2) photon (http://doi.org/10.1351/goldbook.P04627).
3) frequency (http://doi.org/10.1351/goldbook.F02525).

Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 326 (https://doi.org/10.1351/pac200779030293)

Citation: 'downconversion' 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.DT07362

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