The Possibility of Integrating NV Magnetometer Array by Using Wireless Microwave Excitation and Its Application in Remote Heart Sound Records

Nitrogen-vacancy (NV) centers have potential applications in medical imaging and distributed sensing, for which the integrated NV magnetometer array is needed. However, the microwave (MW) drive module limits the development of the compact NV magnetometer system and array. In this paper, wireless MW is applied to two NV magnetometer systems (Sensor I and Sensor II) innovatively. We verified that the magnetic-field sensitivity was approximately equal to 77.1 nT•Hz−1/2 and 44.6 nT•Hz−1/2 for Sensor I and Sensor II, respectively, when the distance between the transmitting and receiving antennas was 1 m. This method can be extended to the NV magnetometer array. The receiving antenna and power amplifier are integrated into the NV magnetometer array system for miniaturization. This expands the utility of NV magnetometers in sensing and medical imaging. Furthermore, we achieved remote heart sound records with a signal-to-noise ratio (SNR) of 5.93 dB and 4.68 dB for Sensor I and Sensor II, respectively, by applying the principle of NV-based demodulator to the system. This would further extend the advantages of the wireless MW in the NV magnetometer. The NV magnetometer could receive the frequency point carrying heart sound signal to reach up to 16, which can avoid the interference of the 2.4 GHz frequency band of Bluetooth and Wi-Fi in complex environments.