Detector imperfections in photon-pair source characterization

TL;DR

This paper investigates how detector imperfections, such as noise and inefficiency, affect the characterization of photon-pair sources, providing exact formulas to assess their impact on quantum optics measurements.

Contribution

It introduces precise calculations for the effects of detector imperfections on key quantum optics parameters, aiding more accurate source characterization.

Findings

Detector noise reduces measured correlations.

Multi-pair emissions influence the Cauchy-Schwarz parameter.

Dark counts affect interference visibilities.

Abstract

We analyze how imperfections in single-photon detectors impact the characterization of photon-pair sources. We perform exact calculations to reveal the effects of multi-pair emissions and of noisy, non-unit efficiency, non photon-number resolving detections on the Cauchy-Schwarz parameter, on the second order auto-correlation and cross-correlation functions, and on the visibilities of both Hong-Ou-Mandel and Bell-like interferences. We consider sources producing either two-mode squeezed states or states with a Poissonian photon distribution. The proposed formulas are useful in practice to determine the impacts of multi-pair emissions and dark counts in standard tests used in quantum optics.