Enhanced Electric Field Sensing with Nitrogen-Vacancy Ensembles

Nitrogen-vacancy (NV) centers in diamond have shown promise as inherently localized electric field sensors, capable of detecting individual charges with nanometer resolution. Here, we demonstrate that a detailed understanding of the internal electric field environment in NV ensembles enables enhanced sensitivity in the detection of external electric fields. We follow this logic along two complementary paths. First, using excitation tuned near the NV’s zero-phonon line, we perform optically detected magnetic resonance (ODMR) spectroscopy at low temperatures in order to precisely measure the NV center’s excited state susceptibility to electric fields. In doing so, we show that a characteristically observed contrast inversion arises from an interplay between spin-selective optical pumping and the NV centers’ local charge distribution. Second, motivated by this understanding, we propose and analyze a novel scheme for optically enhanced electric field sensing using NV ensembles; we estimate that our approach should enable an improvement in DC sensitivity by two orders of magnitude.