Absolute calibration of an EMCCD camera by quantum correlation linking photon counting to analog regime

TL;DR

This paper presents a method for absolute calibration of an EMCCD camera across both analog and photon counting regimes using quantum correlations, linking two traditionally separate measurement standards.

Contribution

It introduces a unified calibration approach that connects analog and photon counting regimes of EMCCD cameras through quantum correlation techniques.

Findings

Calibration method works across regimes by adjusting quantum source brightness.

Analog regime efficiency predicts photon counting behavior accurately.

Establishes a standard bridge between different optical measurement regimes.

Abstract

We show how the same set-up and procedure, exploiting spatially multi-mode quantum correlations, allows the absolute calibration of a EMCCD camera from the analog regime down to the single photon counting level, just by adjusting the brightness of the quantum source. At single photon level EMCCD can be operated as an on-off detector, where quantum efficiency depends on the discriminating threshold. We develop a simple model to explain the connection of the two different regime demonstrating that the efficiency estimated in the analog (bright) regime allows to accurately predict the detector behaviour in the photo-counting regime and vice-versa. This work establishes a bridge between two regions of the optical measurements that up to now have been based on completely different standards, detectors and measurement techniques.