Sidebands in optically detected magnetic resonance signals of nitrogen vacancy centers in diamond

We study features in the optically detected magnetic resonance (ODMR) signals associated with negatively charged nitrogen-vacancy (NV-) centers coupled to other paramagnetic impurities in diamond. Our results are important for understanding ODMR line shapes and for optimization of devices based on NV- centers. We determine the origins of several side features to the unperturbed NV- magnetic resonance by studying their magnetic field and microwave power dependences. Side resonances separated by around 130 MHz are due to hyperfine coupling between NV- centers and nearest-neighbor C-13 nuclear spins. Side resonances separated by approximately {40, 260, 300} MHz are found to originate from simultaneous spin flipping of NV- centers and single substitutional nitrogen atoms. All results are in agreement with the presented theoretical calculations.