Comparison of power spectra in diamond at 2.5 GHz for nitrogenic defects*

For optimal quantum control of point defects in diamond it is important to have a thorough understanding of the noise power spectrum of the defects' environment as this is what determines the coherence times of the spins in quantum information applications. Using a 2.5 GHz pulse electron paramagnetic resonance (pEPR) spectrometer, we examine the properties of the power spectrum in diamond as seen by both the nitrogen-vacancy (NV) center as well as the substitutional nitrogen (P1) center. We perform multi-pulse dynamical decoupling experiments on bulk diamond samples with varying nitrogen concentration. We examine the noise power spectrum for resonant transitions occurring around three main external magnetic field strengths. Near 13 mT and 190 mT we use the NV center as the probe of the environment, and near 89 mT we use the P1 center. We compare the interactions of defect electrons with like and unlike electrons and carbon-13 nuclei and quantify how these interactions affect coherence times.