Generation of third-order parametric down-conversion photons via weak nonlinearities

A higher-order parametric down-conversion (PDC) photon state is amazingly different from the states involving independent photon pairs. We focus on the third-order PDC photons. Firstly, we present a symmetry detector which is capable of analyzing twin-beam six-photon symmetric states in the regime of weak nonlinearities. By cascading symmetry detectors, then, it is shown that one can generate third-order PDC photons from a class of twin-beam six-photon symmetric states. Finally, as an example, we describe an application of third-order PDC photons for exploring six-mode-photon entangled states with linear optics.

Automated summary

This article explores the differences between higher-order parametric down-conversion (PDC) photon states and states involving independent photon pairs, with a focus on third-order PDC photons. By utilizing symmetry detectors and cascading operations, the generation of third-order PDC photons from twin-beam six-photon symmetric states is achieved, showcasing their application in exploring six-mode-photon entangled states with linear optics.