Photoactivation of NV Centers in Diamond via Continuous Wave Laser Illumination of Shallow As-Implanted Nitrogen

Abstract

Negatively charged nitrogen-vacancy (NV−) centers in diamond are appealing for quantum sensing applications due to their environmental sensitivity and long coherence times. Precise and scalable shallow color center creation is essential yet challenging for technological quantum applications. This is due to the involvement of several lengthy processes, such as ion implantation and thermal annealing of the samples. The latter process can be addressed by application of an alternative activation technique that bypasses the high-temperature annealing. For this, nitrogen-implanted regions on a diamond substrate are exposed to continuous-wave 405 nm laser radiation. The illumination leads to local activation of NV− centers with photoluminescence yield saturation for regions activated with laser power at around 800 µW. For low implantation doses, single NV− centers are created with corresponding mean T2 coherence time value around 71 µs. The NV− creation yield for the lower implantation doses match conventional creation methods, while higher doses show reduced yield values. However, the coherent properties are comparable to NV− centers within annealed samples. This shows that the activated NV− centers are well-suited for advanced applications in quantum sensing and related technologies.