Spontaneous parametric down-conversion

Parameter under fluorescence is defined as the conversion of a photon to two secondary photons in a nonlinear optical crystal. The secondary photons have half the energy of the Ausgangsphotons and can be entangled with each other in several ways.

A distinction is made in this so-called " three -photon parametric fluorescence ," the spontaneous parametric Fluorenzenz of the parametric amplification.