Real-Time Magnetic Field Sensing based on Microwave Frequency Modulated Photocurrent of Nitrogen-Vacancy Centers in Diamond

TL;DR

This paper demonstrates real-time magnetic field sensing using microwave frequency modulated photocurrent in nitrogen-vacancy centers in diamond, achieving sensitivities in the nanotesla range and tracking alternating magnetic fields.

Contribution

It provides the first real-time magnetic field tracking with PDMR in NV centers, combining theoretical and experimental analysis to advance practical quantum sensing.

Findings

Achieved magnetic field sensitivities of 397 nT/Hz and 921 nT/Hz.

Demonstrated real-time tracking of alternating magnetic fields with 1.5 μT standard deviation.

Confirmed the dependence of PDMR contrast and sensitivity on laser and microwave power.

Abstract

While photoelectric detection of magnetic resonance (PDMR) can be applied to miniaturize nitrogen-vacancy (NV) center-based quantum sensors, real demonstration of PDMR-based magnetic field sensing remains as a distinctive challenge. To tackle this challenge, in this article, we fabricate diamond samples with electrodes and microwave antenna on the surface, and realize PDMR by detecting photocurrent in picoampere range via various lock-in amplifying modes. We obtain a theoretical and experimental sensitivity 397 nT/Hz and 921 nT/Hz of magnetic field detection in DC-10 Hz range with a laser intensity and microwave frequency modulation mode, respectively, and demonstrate for the first time, a real-time tracking of alternating magnetic field with a standard deviation of 1.5 uT. Furthermore, we investigate systematically the dependence of the PDMR contrast, linewidth and the sensitivity on the laser and microwave power, and find a perfect agreement with a master equation-based theory. Thus, our results represent a critical step forward in transitioning PDMR from a spectroscopic technique to a practical sensing modality.