Quantum Radiometry Project

Accurate knowledge of a single-photon detector’s efficiency is a prerequisite for applications that rely on quantum effects. Also, single-photon counting offers the unique capability of measuring optical power by counting photons at the shot noise limit. To date, no such photon-counting-based standard exists. However, the international system units will soon be recast to be based on fundamental constants and laws of nature. Part of the new quantum SI could be a source- or detector-based single-photon standard. For this reason, many National Metrology Institutes (NMIs) around the world are pursuing to establish traceable or absolute calibration of single-photon detectors and sources. The primary goal of the project is to establish quantum-based absolute traceable sources and detectors for the United States and the world.