Metrological Characterisation of Single Photon Sources and Detectors

Quantum Metrology

A radiometric calibration technique, typically applied in the field of fibre coupled detectors, is used to determine the relative quantum efficiency of single-photon counting avalanche photo diodes (APD).With this method no calibration of the elements in the optical path is needed.
For calibration purposes non-classical photon sources with different g²(0) values are used. These were realized based on the laser-induced fluorescence of nitrogen vacancies in nano diamonds. The nano diamonds are distributed on a silicon wafer and are localized by piezoelectric scanning of the sample. The excitation of the centres and detection of emitted light are performed with a confocal microscope setup.
First measurements show, that a radiometric calibration method can be applied to determine relative quantum efficiency of single photon detectors. The achieved standard uncertainty is 0.02.
Further investigations are needed to determine the influence of the statistics of single/multi photon emission, dead time and jitter of the detection system on the calibration results.
It is also possible to use other single-photon sources for the calibration, which show different properties with respect to spectral behaviour and quantum efficiency.

TU Braunschweig
in progress
Ph.D. student: