Wide-field Imaging Of Magnetic Field And Temperature Based On Ensemble NV Color Centers In Diamond

The imaging detection and characterization of the magnetic characteristics and temperature distribution at the micro and nano scales are very important in many science and technology fields.For example,the detection of magnetic field characteristics of the magnetic domain and magnetic micro nanoparticles,the analysis of Ostian magnetic field distribution caused by moving charge and the detection of temperature and heat distribution of electrified equipment,etc.The magnetic field and temperature imaging detection can help us to have a deep understanding of magnetic/thermophysical properties of materials in materials science,the transmission mechanism of semiconductor physical media,the working principle,service life and failure mechanism of electrified equipment,etc.However,the current magnetic field and temperature imaging detection technology are often limited by the detection sensitivity or spatial resolution,or incompatible with the sample,or imaging range and other factors.Therefore,it is of great significance to directly test magnetic field and temperature imaging with multi parameters consideration.In recent years,the solid-state spin system has formed an increasingly influential quantum sensing platform.In particular,the nitrogen-vacancy?NV?color center,an atomic-scale defect in diamond,is taken as a representative.Because of the advantages of long spin life at room temperature,coherent microwave spin manipulation,optical spin initialization and readout,and good biocompatibility,the sensing method based on NV color center has a wide range of practicability.Its application research covers condensed matter physics,neuroscience,and life system biology,nuclear magnetic resonance,earth,and Planetary Science,industrial vector magnetometer,etc.Compared with the point acquisition of the quantum sensor,the imaging test is the acquisition of field information,which can realize the field representation and reconstruction of target information.Based on this,the research on the wide-field imaging technology of magnetic field and temperature based on the NV color centers in diamond in this paper includes:1)Based on the sensitive mechanism of magnetic field and temperature detection,the methods of contrast,uniaxial,triaxial vector and temperature imaging are proposed,and the detection decoupling of magnetic field and temperature information is realized by double resonance point solution technologyFor wide field imaging detection based on ensemble NV color centers,the sensitivity mechanism of the magnetic field and temperature is discussed.Based on this,the methods of contrast magnetic imaging,uniaxial magnetic imaging,triaxial magnetic imaging and temperature imaging are studied.For three-axis vector magnetic imaging,through the establishment of the solution model,the specific implementation method of detecting vector magnetic field using ensemble NV color center is studied in detail.At the same time,aiming at the coupling problem of magnetic field and temperature information in the imaging process,the detection decoupling is realized by using double resonance point solution technology.2)Through the preparation of diamond color center with high concentration and the design and development of wide field uniform microwave radiation antenna,combined with the confocal imaging system,the construction of diamond color center imaging system is completedAccording to the demand of high concentration NV color centers,based on the color center fluorescence and spin concentration,the evaluation method of concentration and sensing characteristics is established,and the optimized preparation of sensitive unit is realized.Aiming at the demand of controllable spot and adjustable laser power,and taking into account the high efficiency of NV color center fluorescence excitation and collection,an integrated imaging optical path system composed of optical precise control optical path system and confocal system is designed and built.In order to meet the needs of high power and wide uniform microwave radiation,a microwave system consisting of microwave source,microwave power amplifier,circulator and radiation antenna is designed and built.At the same time,as the carrier of microwave radiation,the performance of antenna directly determines the uniformity of the required radiation microwave field.A dual ring stereo microwave radiation antenna is designed and developed.Compared with the traditional line antenna and single ring antenna,the dual ring stereo microwave antenna achieves a uniform area of 4?mm ²×2 mm,and its sensitivity can be increased by 4.93 times and 9.98 times.According to the demand of multi resonance ODMR spectrum of NV color center in ensemble,the bias magnetic field system is studied comparatively.At last,the synchronous control system and data processing system,including the camera,pulse board,and other experimental devices,as well as the control software and the calculation software are studied.On this basis,we successfully built an imaging system based on the ensemble diamond NV color center.3)Through the wide field imaging research on the typical magnetic field and temperature of the electrified wire,magnetic suppression heating chip and circuit board,the application test is realized,and the system sensitivity and spatial resolution are discussed in detailIn the part of the experimental investigation,we use the imaging system to image a single wire,a magnetic suppression heating chip,and a circuit board.The experimental results are consistent with the simulation results.These experimental results show that our wide-field magnetic field and temperature imaging system based on the NV color centers in diamond has a good magnetic field and temperature imaging ability.The sensitivity and spatial resolution of the system are discussed and calculated.The correlation calculation and the test data of the system show that the detection sensitivity of magnetic field imaging can reach 1.8?T/Hz^1/2,and the detection sensitivity of temperature imaging can reach 0.4 K/Hz^1/2.At the same time,the spatial resolution of the system can reach sub?m,and the imaging detection area can reach 400×300?m².