Metrology Perspective of Single‐Photon Detectors: Review on Global Calibration Methods

Abstract The evolution of quantum standards for SI units and funding support from national governments has led to rapid technological developments in the quantum sciences. With this, new and more powerful quantum optical devices that find applications in several fields are obtained. Single‐photon detectors (SPDs) are considered as a critical element in these emerging technologies. A traceability chain for SPD calibration is required to ensure their performance reliability and quality. Different methods and techniques are being developed worldwide for the calibration of SPDs. In this paper, the developments that have occurred globally in SPD calibration and the uncertainty value achieved until now are summarized along with the scope of possible improvement areas.