Multi-frequency ODMR of Nitrogen-Vacancy Color Centers in Diamond Crystals in zero magnetic fields

Abstract

Techniques of optical detection of magnetic resonance, as applied tothe nitrogen-vacancy center in diamond, provide a tool for controlling both electron and nuclear spins. These techniques generally use a combination of microwave (MW) drive field for electronic spin transitions and radiofrequency (RF) drive field for nuclear spin transitions. They are most effective in strong magnetic fields where levels anticrossing (LAC) occurs; therefore NV spin system dynamics is mostly studied under these conditions. Nevertheless, zero-field LAC can probably also be used for controlling electron and nuclear spin states as well for exciting narrow resonances for metrological application, and these perspectives are not yet properly investigated. Here we present two-quantum resonances appearing in ODMR spectra of NV centers in bulk diamond under multi-frequency (MW+RF) resonance excitation in zero and ultra-low magnetic fields, and discuss their specifics.