Magnetic field sensitivity of the photoelectrically read nitrogen-vacancy centers in diamond

Abstract

In this work, we report on the sensitivity of photo-electrical detection of magnetic resonances (PDMR) for magnetometry measurement using low density nitrogen vacancy (NV) ensembles in CVD-grown diamond. We demonstrate that the selection of the laser excitation wavelength is of importance for achieving optimal magnetic field sensitivity. The PDMR sensitivity obtained using a yellow-green (561 nm) laser surpasses the performances of a green laser (532 nm), by suppressing the photoionization of defects other than NV centers (such as P1 centers). It consequently allows to carry out the PDMR measurements at lower laser powers with increased magnetic resonance contrast. Noticeably for both the green and the yellow-green illuminations, PDMR leads to an improved sensitivity to magnetic fields in the selected conditions compared to optically detected magnetic resonance.