Workpackage 1: Single-photon sources based on impurity centres in diamond

Within this workpackage, predictable compact absolute single-photon sources based on nitrogen- and silicon vacancy centres (NV-centre, SiV-centre, respectively) in diamond nanocrystals will be developed. This requires the production of defect centre doped nanocrystals, their implementation into metallo-dielectric structures allowing for near-unity collection efficiency, the characterisation of the sources in terms of photon flux, emission wavelength, emission linewidth and lifetime, g(2) value and photon statistics. Furthermore, the source will be adjustable in terms of the single-photon repetition rate, allowing, for the first time, calibrations over a wide range of photon fluxes.

Workpackage 2: High brightness single-photon sources based on quantum dots and photonic waveguides

Within this workpackage, highly efficient, electrically pumped and compact single-photon sources will be developed, with photon fluxes of up to 107 photons per second, with near unity collection efficiency based on semiconductor quantum dots. This requires using molecular beam epitaxy (MBE) to fabricate InAs/GaAs quantum dots (QD) emitting in the spectral range between 900 nm and 950 nm, the design of the appropriate structure to realise near unity collection efficiency for optically and electrically pumping with the help of numerical modelling, and characterisation with respect to photon rate, g(2)-value, photon statistics, and spectral and temporal characteristics.

Workpackage 3 Entanglement enhanced measurements

This workpackage will provide new sources of quantum optical states with non-classical state correlations that will improve the accuracy and the sensitivity of measurements beyond the standard quantum limit (SQL), also referred to as the shot noise limit (SNL). The most suitable of the single-photon sources developed in workpackages 1 and 2 that satisfy the requirements for creating non-classical correlations will be used to create these states. The degree of measurement enhancement produced by using these states will be quantified, and the consequences for other quantum enhanced measurement (QEM) schemes assessed.

Workpackage 4: Impact

The results of this JRP will enable academic institutions and industry working in the emerging field of quantum communication to exploit the proposed single-photon sources and quantum based measurement techniques. Furthermore, the outcome of this project will stimulate and enable new metrological methods and techniques in the NMIs.
The results of this project will be disseminated at international conferences, workshops and seminars, thus reaching a community far beyond the metrological community. Methods and procedures developed within this project will be able to be harnessed by the larger industrial and academic community, thus leading to further development of the sources and quantum based measurements.

Workpackage 5: Management and Coordination