Tripartite entanglement and threshold properties of coupled intracavity downconversion and sum-frequency generation

TL;DR

This paper investigates the complex threshold behavior and entanglement properties of a coupled intracavity downconversion and sum-frequency generation system, revealing rich entanglement features influenced by pump quantization.

Contribution

It extends previous analyses by including pump quantization effects, uncovering diverse threshold phenomena and asymmetric entanglement in a singly pumped cavity system.

Findings

Rich threshold behavior due to pump quantization.

Asymmetric polychromatic entanglement over wide parameters.

Enhanced understanding of entanglement in coupled nonlinear processes.

Abstract

The process of cascaded downconversion and sum-frequency generation inside an optical cavity has been predicted to be a potential source of three-mode continuous-variable entanglement. When the cavity is pumped by two fields, the threshold properties have been analysed, showing that these are more complicated than in well-known processes such as optical parametric oscillation. When there is only a single pumping field, the entanglement properties have been calculated using a linearised fluctuation analysis, but without any consideration of the threshold properties or critical operating points of the system. In this work we extend this analysis to demonstrate that the singly pumped system demonstrates a rich range of threshold behaviour when quantisation of the pump field is taken into account and that asymmetric polychromatic entanglement is available over a wide range of operational parameters.