Research On Wide-field Vector Imaging Technology Based On Ensemble NV Color Center

As an emerging solid-state quantum sensing system,the special structural defect Nitrogen-Vacancy(NV)color center in diamond has been intensively studied by many researchers because of its excellent characteristics of working in a room temperature environment and not having biological toxicity.High-precision magnetic vector imaging on the surface of chips and chip-like structures is an important detection method for thermal parameter testing when the core components of the device are working.The magnetic vector imaging technology that uses NV color center as a probe for chip nondestructive testing has broad research prospects.This is because of the C_3v symmetry of the diamond NV color center,and the quantum state of the electron spin of the NV color center can be manipulated through microwave resonance.And can read the vector information of the magnetic field at the position of the NV color center according to the change of its radiated red photoluminescence(PL).According to the high-concentration characteristics of ensemble diamond,it is regarded as a collection of multiple magnetic sensitive units uniformly distributed in a wide field range,and a camera can be used to realize a wide field of view imaging of a magnetic field.The basic research content of this paper is to explore a wide-field microscope magnetic vector imaging technology based on the NV color center of ensemble diamond based on the vector magnetic sensitivity characteristics of the NV color center of the ensemble diamond.Based on this,a verification experiment of magnetic field vector imaging is designed,and the test sample used is a self-made miniature magnetic structure that is energized.The thesis first explored the existing magnetic imaging technology,focusing on the investigation of the related research of magnetic field vector imaging based on the ensemble diamond NV color center at home and abroad.Afterwards,starting with the energy level transition and lattice structure of the diamond NV color center,the magnetic field sensitivity principle and vector detection basis of the NV color center are explained.A magnetic field reduction model is constructed through the established spatial coordinate system for component conversion of the magnetic field in the NV axis.The continuous wave optically detected magnetic resonance(CW-ODMR)technology is used to obtain the ODMR spectrum curve of the red fluorescence with the microwave frequency,and the vector information of the magnetic field can be derived based on the eight resonance frequencies extracted from it.Secondly,a wide-field microscope magnetic vector imaging experimental platform based on the ensemble diamond NV color center was designed,and the optical path system was built.After the ensemble diamond with uniform NV color centers is obtained,the electronic spin state is manipulated by stepping microwave and bias magnetic field.According to the synchronization sequence,the ODMR spectrum of the stable red fluorescence emitted by the green laser fully polarized by the NV color center is obtained.Write a data processing algorithm to extract the eight resonance frequency points,and calculate the vector imaging result of the sample magnetic field.And the spatial resolution of the system can reach 1?m/pixel.Finally,the experimental platform was used in the magnetic field imaging experiment of two kinds of laboratory self-made samples.The first sample is a single micro-wire with a PCB board as the base.The magnetic field generated by the energization of the single micro-wire was subjected to vector imaging,and the imaging experiment was carried out with different experimental parameters according to the simulation results.When using the best microwave power and laser power provided by the experimental platform,the magnetic sensitivity at a single imaging pixel in the obtained magnetic field imaging results can reach 20?T/Hz^1/2.The second sample is a part of the complex structure on the surface of the folded-back magnetic suppression heating chip designed in the laboratory.The magnetic field generated after it is energized is imaged,and the magnetic vector imaging result that matches the direction is obtained.In addition,the conclusions based on the research content of this paper are put forward,and the development of NV color center magnetic vector imaging technology is prospected.