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: \[\nu _{1}=\nu _{2}+\nu _{3}\]
  1. Also known as a parametric downconversion.
  2. 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.
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 326 (