Producing optimized ensembles of nitrogen-vacancy color centers for quantum information applications

Quantum information applications place stringent demands on the development of platforms that can host them. Color centers in diamond have been identified as important media for quantum information processing. Accordingly, the photoluminescence properties of nitrogen-vacancy (N-V) centers in diamond created by implantation and annealing are studied at cryogenic temperatures (below 10 K). We examine high pressure high temperature and chemical vapor deposition synthetic diamonds with varying nitrogen concentration and present an accurate method to estimate the concentration of the (N-V) centers created by ion implantation. The ion irradiation route produced up to 6 ppm of optically active (N-V) centers, while nitrogen implantation yielded up to 3 ppm of optically active (N-V) with 8% conversion efficiency. However, a broadening of the (N-V)- zero phonon line was observed in all samples.