Optimising the use of detector arrays for measuring intensity correlations of photon pairs

TL;DR

This paper analyzes how multi-element detector arrays can optimize the measurement of intensity correlations in photon pairs, providing theoretical predictions and experimental validation using an EMCCD camera.

Contribution

It introduces a theoretical framework for optimizing detector array parameters to enhance correlation visibility and validates it through experiments with an EMCCD camera.

Findings

Optimal mean detected photons equal to noise events for maximum visibility

Derived expressions for correlation strength based on detector parameters

Experimental results agree with theoretical predictions

Abstract

Intensity correlation measurements form the basis of many experiments based on spontaneous parametric down-conversion. In the most common situation, two single-photon avalanche diodes and coincidence electronics are used in the detection of the photon pairs, and the coincidence count distributions are measured by making use of some scanning procedure. Here we analyse the measurement of intensity correlations using multi-element detector arrays. By considering the detector parameters such as the detection and noise probabilities, we found that the mean number of detected photons that maximises the visibility of the two photon correlations is approximately equal to the mean number of noise events in the detector array. We provide expressions predicting the strength of the measured intensity correlations as a function of the detector parameters and on the mean number of detected photons. We experimentally test our predictions by measuring far-field intensity correlations of spontaneous parametric down-conversion with an electron multiplying CCD camera, finding excellent agreement with the theoretical analysis.