A Low-Frequency AC Electric-Field Amplitude Reconstructed Method Based on Nitrogen-Vacancy Center in Diamond

Electric-field measurement in emerging power systems requires compatibility with multiple frequency bands, high field strengths, and complex electromagnetic environments. This study proposes a low-frequency AC electric-field amplitude reconstructed method based on the nitrogen-vacancy (NV) center in diamond. A Hahn–echo sequence converts the electric-field-induced quantum phase accumulation into NV fluorescence variations, and the field amplitude is retrieved through time-domain fitting and frequency-domain feature extraction. A parallel-plate electric-field generator was first calibrated using a standard electro-optic probe, followed by measurements at 2500 Hz. With the electro-optic probe result as the reference, the reconstructed electric-field amplitudes showed good quantitative agreement in the moderate-field range, with a best single-point absolute deviation of 0.0219 kV/m, while larger deviations were observed at the lower and higher ends of the tested amplitude range. By adjusting the Hahn–echo sequence to match different field periods, amplitudes at 1500 Hz and 2000 Hz were also successfully retrieved. The results demonstrate that the method is applicable to narrowband AC electric fields at known frequencies within a certain range, supporting an experimental basis for applying quantum sensing technology to power-equipment condition monitoring and measurements in complex electromagnetic environments.