Ensembles of nitrogen-vacancy (NV) centres in diamond are a leading platform for practical quantum sensors. Reproducible and scalable fabrication of NV-ensembles with desired properties is crucial, as is an understanding of how those properties influence performance. This work addresses these issues by characterising nitrogen-doped diamond produced by the chemical vapour deposition (CVD) method across a range of synthesis conditions. This is shown to produce material with widely differing absorption characteristics, which is linked to the level of defects other than substitutional nitrogen (NS) and NV. In such material, the achievable concentration of NV− ([NV−]) is found to be influenced by the as-grown properties. At the 10–20 ppm level for [NS], the production of CVD-grown material with strain levels sufficient not to limit achievable device sensitivity is demonstrated and a favourable product of [NV−] and T 2 * is obtained. Additionally, reproducible properties over a batch of 23 samples from a single synthesis run are achieved, which appears promising for the scalability efforts underway in this area of research.

No abstract

No abstract

Results are presented for an adiabatic quantum algorithm to compute low peak sidelobe binary and unimodular codes on a D-Wave 2 quantum computer. The quantum algorithm is benchmarked against a conventional genetic algorithm (GA). The quantum algorithm shows roughly a 100 times speedup relative to the GA for binary codes longer that 100 bits and is capable of producing low sidelobe binary codes up to length 426 on the current D-Wave 2 hardware. Results are presented for Doppler tolerant binary and quad-phase codes computed using the same quantum algorithm.

No abstract