Optimization of the Double Electron–Electron Resonance for C‐Centers in Diamond

Nitrogen‐vacancy (NV) centers in diamond recommend themselves as good sensors of environmental fields as well as detectors of diamond impurities. In particular, C‐centers, often also called p1‐centers, can be detected via double electron–electron resonance. This resonance can be used to measure the C‐center concentration. Herein, the concentration of C‐centers in several diamond plates is measured and the influence of the free precession time of the NV‐center on the observed contrast in the measured double electron–electron resonance spectrum is investigated. The dependence of the resonance amplitudes and widths on the concentration of C‐centers as well as the length of the combined C‐center driving and NV‐center π‐pulse is also discussed. The optimal contrast‐free precession time is determined for each C‐center concentration, showing a strong correlation with both the concentration of C‐centers and the NV‐center T2 time. The concentration of C‐centers in several diamond plates is measured. The influence of the free precession time of the nitrogen‐vacancy (NV) center on the contrast in the double electron–electron resonance spectrum is investigated. The optimal free‐precession time is determined for each C‐center concentration, showing a strong correlation with both the concentration of C‐centers and the NV‐center coherence time.