Noninvasive Imaging Method of Microwave Near Field Based on Solid-State Quantum Sensing

In this paper, we propose a noninvasive method of imaging the microwave (MW) near field using a diamond containing nitrogen-vacancy (NV) centers. We applied a synchronization pulsed sequence combined with a camera to measure the amplitude of the MW magnetic field. A full reconstruction formulation of the local field vector, including the amplitude and phase, is developed by measuring both the left and right circular polarizations along the four NV axes. Compared to the raster scanning approach, the imaging method is more time efficient and more stable because of absence of any moving parts in the system. A diamond film with micrometer thickness enables high-resolution near-field imaging. The proposed method is expected to have applications in local diagnosis on monolithic MW integrated circuits chip, antenna characterization, and the field mode imaging of MW cavities and waveguides.