Dual-Photodetectors Microwave Near-Field Magnetometer Based on Nitrogen-Vacancy Centers Diamond

Near-field magnetic field measurements are an important means to comprehensively evaluate the electromagnetic compatibility (EMC) of integrated circuits (ICs). In this paper, we propose an innovative Nitrogen-Vacancy (NV) centers diamond near-field measurement device equipped with dual-photodetectors for EMC analysis of ICs. We designed a dual-photodetectors multiplexed optical path system compatible with the near-field scanning and imaging functions. Then, we designed a variable laser-shaping optical path system with a high-amplification photodetector to achieve fast magnetic field measurements with variable spatial resolution. Finally, we designed a new synchronization control system to meet the different requirements of the two photodetectors for the measurement sequence. The new device avoids the problem of traceability of measurement results caused by switching the device type of existing devices for different scales of near-field measurements due to the multiplexing of optical paths and components. At the same time, the use of fewer components makes the new device more economical. Most importantly, the new device can change the spatial resolution to match the probe scale with the measurement scale, which improves the measurement efficiency based on ensuring the measurement effect. The proposed device has good application prospects in the fields of online EMC testing of ICs and rapid screening and diagnosis of antenna faults.