Research On High Precision Current Sensing Method Based On Diamond NV Color Center

As a basic physical quantity,current is of great significance for its accurate measurement.Researchers have been exploring various methods to measure current.After years of development of current measurement technology,discovering the range of current measurement methods,from direct to indirect,and the measurement principle from electric field to magnetic field,is not a difficult task.Thus,numerous current sensors can be thought of as magnetic sensors.However,no matter which current sensing method has its own measurement limitations,and there is a common problem that linearity is not high enough to break through ppm level,can not be used in the field of precision measurement,such as the calibration of various high-precision equipment,so it is urgent to introduce a new principle to develop a new mechanism of current sensing method on the market.The nitrogen vacancy（NV）color center in diamond is a very special defect,which has excellent luminescence and spin properties,making it the focus of current research.In addition,it can also convert changes in the external environment into spin related information,so as to realize the measurement of a variety of physical quantities,such as magnetism,electricity,temperature field,etc.By combining the sensitivity of diamond NV color center with a magnetic gathering structure,this paper presents a novel current sensing technique that utilizes NV color center’s magnetic measurement principle to attain high accuracy in current measurement.This paper first introduces the research of diamond NV color core magnetic sensing and current sensing technology,and leads to the research of diamond NV color core electrical transmission sensing method.Based on Hamiltonian equation,a diamond NV color center magnetic sensing model was established.The basic structure,spin level structure,transition mechanism and high concentration preparation process of NV color center were analyzed.Then the measurement principle of magnetic resonance detected by spin structured light is explained and the magnetic measurement mechanism of diamond NV color center is analyzed.Then,by combining the two methods,based on implementation experiment,a new current sensing method based on NV color center is provided,as per the essential element of Hall current sensor structure.Then the structure of diamond NV color center current sensor is designed,which mainly includes three parts.The optical path module is used to excite and collect the fluorescence of NV color center.The magnetic aggregation module aggregates the magnetic field around the current conductor to form a stable and uniform magnetic field in the air gap for NV color center measurement.The microwave module applied resonant microwave energy to the NV color center to achieve magnetic resonance measurement.In addition,the separate design of magnetic ring is emphasized,which mainly includes material selection,structure size,air gap parameter design and finite element simulation of structure performance.Finally,the experimental platform and performance test characterization of the diamond NV color center current system are carried out.The design of the current sensor has been demonstrated to be highly effective,with ultra-high linearity across a broad range of measurements,up to 33 ppm.When the input current ranges from 5 to 40 A,the absolute error in calculating the current is less than 51μA.The relative error is 2.42×10^-6at 40 A.Moreover,the long-term stability of the sensor is good,and the stability error within 1h is less than 0.0002 A.The outstanding advantages of current sensor can ensure that it will have a very broad application prospect in the field of precision measurement.