Vectorial Near-Field Characterization of Microwave Device by Using Micro Diamond Based on Tapered Fiber

Microwave vectorial near-field precision physical quantity sensing using ensembles of nitrogen vacancy (NV) centers in diamond has attracted much interest in recent years. The quantum probe of a micron-sized diamond particle attached to a tapered fiber has been widely studied for applications in condensed matter physics, bioscience and electromagnetics. A general issue of Microwave (MW) field vectorial sensing using the probe describe above is the orientation of the NV axes to specified directions in the lab frame. In this work, we propose a practical method for characterizing the MW vectorial near-field by using the quantum probe. The orientations of the NV axes in the lab frame are measured first by using 3-axis Helmholtz coils. The NV axis also needs to be rotated to any specified direction for sensing the MW vectorial near-field component on the perpendicular plane. We demonstrate coplanar waveguide (CPW) vectorial near-field characterization using this micrometer-sized probe, and the proposed method is expected to be applied in the field of millimeter wave imaging with nanometer spatial resolution.