Vector Magnetometry Using Nitrogen-Vacancy Center In Diamond Integrated With Optical Vortex Beam

Magnetic field measurement is widely used in scientific research,industrial production,national defense and military fields.It has attracted the attention of many researchers especially in the brain magnetism,biological neuromagnetic field,material science,data storage and nuclear magnetic resonance signal detection and other frontier field.In this paper,a calibration-free vector magnetometer is designed based on the diamond nitrogen-vacancy(NV)center,which realizes the complete reconstruction of vector magnetic field information(including magnetic field size and orientation).Compared with scalar magnetic field detection,vector magnetic field measurement can accurately detect the azimuth information of magnetic anomalies.As a quantum magnetic probe,NV center has the advantages of high sensitivity and high spatial resolution.But,the c_3v symmetry leads to the limitation of magnetic field detection by using single NV center,which can only extract the magnetic field size and the angle between the magnetic field and the axial direction of the NV center.This symmetry can be broken by using three different axial of NV centers to realize vector magnetic field detection.The position and orientation of the NV center inside the diamond are random.In order to realize the detection of vector magnetic field in the laboratory coordinate system,it is necessary to calibrate the axial direction of the NV center.At present,the commonly used methods include:1.Using three-dimensional electromagnet to generate a 360-degree omnidirectional scanning magnetic field,and synchronously measuring the optical detection magnetic resonance spectrum,so as to obtain the axial information of NV center;2.The NV center fluorescence is polarization anisotropic,and the axial calibration of the NV center is realized by continuously changing the polarization direction of the excitation beam.The above two schemes require a long time to calibrate the position and axial direction of the NV center,which will introduce background noise and NV center drift,seriously limit the spatial resolution and sensitivity of vector magnetic field detection,and also hinder its application in dynamic magnetic field measurement.Vortex beam has been widely used in 3D imaging and manipulation of single molecule and gold nanoparticles due to its advantages in the field of single atom and molecule manipulation.In this thesis,vortex field is applied to NV center vector magnetic field detection.Specific research contents are as follows:1.The interaction process between NV center and azimuthally polarized beam is theoretically analyzed.NV centers have double optical dipoles.We simulate their interaction process with azimuthally polarized beam,and analyze the fluorescence scanning images of NV centers with different orientations excited by azimuthally polarized beam.2.The NV center fluorescence image excited by azimuthally polarized beam was measured experimentally,and the NV center in the tangential diamond sample{111}was scanned and four different fluorescence images were obtained.The axial information of NV was extracted from fluorescence images by"theoretical simulation and image matching"method.3.Combined with axial information of NV center and optical detection magnetic resonance spectrum,vector magnetic field detection is realized by using three NV centers with different orientations,and the magnetic field orientation detection sensitivity reaches 0.01 rad.