Correlations in photon-numbers and integrated intensities in parametric processes involving three optical fields

TL;DR

This paper investigates the correlations among three optical fields generated in a nonlinear crystal, developing a quantum theory to analyze their joint statistics and demonstrating nonclassical properties and sub-Poissonian states through conditional measurements.

Contribution

It introduces a microscopic quantum model for three-mode correlated states in parametric processes and explores their nonclassical features and state engineering via conditional measurements.

Findings

Proven nonclassical nature of the three-mode state.

Demonstrated sub-Poissonian statistics in conditional states.

Analyzed the impact of detection efficiencies on state preparation.

Abstract

Two strongly-pumped parametric interactions are simultaneously realized in a single nonlinear crystal in order to generate three strongly correlated optical fields. By combining together the outputs of two of the three detectors measuring intensities of the generated fields, we obtain the joint photocount statistics between the single field and the sum of the other two. Moreover, we develop a microscopic quantum theory to determine the joint photon-number distribution and the joint quasi-distributions of integrated intensities and prove nonclassical nature of the three-mode state. Finally, by performing a conditional measurement on the single field, we obtain a state endowed with a sub-Poissonian statistics, as testified by the analysis of the conditional Fano factor. The role of quantum detection efficiencies in this conditional state-preparation method is discussed in detail.