Research On Magnetic Measurement Based On Diamond NV Color Center Magnetometer

Diamond NV(Nitrogen vacancy)color centers have excellent quantum spin properties,which can measure weak magnetic fields in various working environments at room temperature.Therefore,diamond NV color centers with high sensitivity and excellent spatial resolution properties are widely used in quantum sensing research,especially in the field of weak magnetic detection.The ODMR(Optical Detection Magnetic Resonance)method is the most commonly used method for measuring the static magnetic field of diamond NV color centers.However,the traditional ODMR method requires microwave scanning,which has the problems of long experimental time and high complexity;In addition,due to limitations in usage scenarios and cost control,diamond NV color center magnetic measurement can only be carried out in environments without magnetic shielding shells in most cases,and external magnetic noise interference seriously affects the accuracy of magnetic measurement.In this paper,relevant research has been carried out in view of the shortcomings in the current diamond NV color center magnetic measurement.First,the internal electronic structure of the diamond NV color center and the principle of stimulated emission fluorescence have been introduced theoretically,and the principle of diamond NV color center magnetic measurement has been further expounded with the knowledge of quantum mechanics;Then an efficient reconstruction method based on Lorentz function was proposed,which uses mathematical fitting to obtain the magnetic measurement curve;And analyze and remove noise interference in magnetic measurement experiments to obtain more accurate measurement results.The specific research content of the paper is as follows:Firstly,in response to the problem of the long time required to obtain the curve through sweep frequency in the CW-ODMR(Continuous Wave Optical Detection Magnetic Resonance)method,this paper proposes a random frequency excitation undersampling reconstruction method.It only needs to randomly set a few microwave frequencies,and the fluorescence intensity excited by these frequencies can be used to fit and reconstruct the resonance peak curve,effectively improving the efficiency of measuring magnetic fields using the CW-ODMR method.Secondly,in order to verify the magnetic measurement capability of the diamond NV color center based magnetometer,this paper independently designed and built a magnetic measurement system based on the diamond NV color center,and introduced the functions of each part of the system.And through this system,the curve of diamond NV color center magnetic measurement was obtained,laying the foundation for subsequent research.Thirdly,in order to address the issue of various magnetic noise interferences that the experimental system may encounter when conducting experiments in an environment without magnetic shielding,including geomagnetic fields,power frequency magnetic fields,other magnetic fields,and the magnetic components of microwaves themselves.This paper determines the magnitude and direction of various magnetic field interferences through a combination of simulation and actual measurement.Finally,various magnetic field noises are removed through magnetic field vector compensation,suppressing magnetic noise in an environment without magnetic shielding,Reduced the magnetic field measurement error in ODMR experiments.This article focuses on the magnetic measurement experiment of diamond NV color centers.On the basis of verifying the feasibility of measuring magnetic fields using diamond NV color centers,the shortcomings in the CW-ODMR experiment have been optimized and improved,improving the efficiency of magnetic field detection and the accuracy of magnetic field measurement.