Stimulated and spontaneous down-conversion in layered media

This work continues the study of layered structures, which have proved to be useful for the efficiency of the spontaneous parametric down-conversion similarly as the quasi-phase matching. The effect of pumping is included in the reflection and the transmission of the down-converted fields and is considered this way also within the structure so that the nonlinear structure may be described similarly as a linear layered structure. The generalized complex amplitude reflectances and transmittances are utilized for expression of the input–output relations of quantum fields. These relations are approximately unitary. We express the single photon detection rate and the joint detection rate. We mention the macroscopic approach to quantization which can generate both the time-dependent Maxwell equations.