Term: biphotonic excitation
https://doi.org/10.1351/goldbook.B00668

Definition:
Simultaneous (coherent) absorption of two photons (either same or different wavelength), the energy of excitation being the sum of the energies of the two photons. Also called two-photon excitation.

Note: This term is sometimes also used for a two-step absorption.

Related Terms:
1) absorption (http://doi.org/10.1351/goldbook.A00036).
2) photons (http://doi.org/10.1351/goldbook.P04627).
3) wavelength (http://doi.org/10.1351/goldbook.W06659).
4) two-photon excitation (http://doi.org/10.1351/goldbook.T06541).

Source: PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 308 (https://doi.org/10.1351/pac200779030293)

Citation: 'biphotonic excitation' 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.B00668

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