Optimization of the double electron-electron resonance for C-centers in diamond

TL;DR

This paper improves the double electron-electron resonance technique for detecting C-centers in diamond, optimizing measurement parameters to enhance sensitivity and accuracy in concentration assessments.

Contribution

It introduces an optimized method for D-EPR measurements of C-centers in diamond, analyzing the influence of precession time and pulse parameters on contrast and resonance features.

Findings

Optimal free precession time correlates with C-center concentration and NV-center T2 time.

Resonance amplitude and width depend on C-center concentration and pulse length.

Enhanced measurement accuracy for C-center concentration in diamond plates.

Abstract

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 ${{p}_{1}}$-centers, can be detected via double electron-electron resonance. This resonance can be used to measure the C-center concentration. Here, we measured the concentration of C-centers in several diamond plates and investigated the influence of the free precession time of the NV center on the observed contrast in the measured double electron-electron resonance spectrum. 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 $\pi$-pulse is also discussed. The optimal contrast-free precession time was determined for each C-center concentration, showing a strong correlation with both the concentration of C-centers and the NV-center ${{T}_{2}}$ time.