Relative calibration techniques for characterising single photon detectors

Over the past ten years an increasing interest for improved single photon technology has been come up in research fields as diverse as optical quantum information technology, laser ranging, remote sensing, astronomy or biomedical imaging. In this context metrological validation of single photon sources and detectors are expected to have an immediate impact on further industrial needs of prospective standards and certifications from national metrology institutes (NMIs). Worldwide research programs for absolute single photon detector calibration exist at several NMIs, preferably dealing with parametric down-conversion [1]. Despite of this, a widespread use of various relative calibration techniques is established in order to realise reliable and low uncertainty measurements of the detection efficiency, which is one key parameter characterising single photon detectors.