Quantum Stochastic Dynamics in Multi-Photon Optics

In this work a generic model of \emph{multi-photon optics} is studied. It is considered $m$ pump and $n$ subharmonic fields. It shows how the multi-photon system, with direct and homodyne detection, can be obtained rigorously in the context of \emph{Measurement theory in Open Quantum System} (see \cite{Bar-OQS}, \cite{Bar-1990-QO} and \cite{RCS-LAP}). This is done trough the \emph{Quantum Stochastic Differential Equations} with unbounded coefficients (see \cite{Fagnola-Wills}, and \cite{RCS-LAP}). In particular the existence of the dynamics is proved, and a continuous measurements scheme is provided.