Charge state and photoionization dynamics of surface implanted nitrogen vacancy centers in diamond

Ensembles of surface implanted, shallow nitrogen vacancy centers in diamond are widely used in sensing applications. Although the spin properties of superficial nitrogen-vacancy (NV) centers have been the subject of extensive scrutiny, considerable less attention has been devoted to studying the dynamics of NV charge conversion near the diamond surface. Using multi-color confocal microscopy, here we show that surface states dramatically increase the ionization and recombination rates of shallow NVs compared to those in bulk diamond. Further, we find that these rates grow linearly, and not quadratically, with laser intensity, and that the underlying charge processes ultimately impact the ability to spin-initialize NV^-. In spite of the altered charge dynamics, we show we can imprint rewritable,patterns of charged-initialized, near-surface NVs over large areas, an ability that could be exploited for electrochemical biosensing or to demonstrate sub-diffraction optical data storage.