Long-Lived Ensembles of Shallow NV Centers in Flat and Nanostructured Diamonds by Photoconversion.

Shallow, negatively charged nitrogen-vacancy centers (NV) in diamond have been proposed for high-sensitivity magnetometry and spin-polarization transfer applications. However, surface effects tend to favor and stabilize the less useful neutral form, the NV centers. Here, we report the effects of green laser irradiation on ensembles of nanometer-shallow NV centers in flat and nanostructured diamond surfaces as a function of laser power in a range not previously explored (up to 150 mW/μm).