All-optical vector magnetometry based on fine and hyperfine interactions in spin-32 centers in silicon carbide

The possibility of using axial spin centers with S=3/2 in silicon carbide for all-optical measurement of the projection Bz of the external magnetic field onto the c-axis of the SiC crystal, as well as the polar and azimuthal angles of the magnetic field relative to the direction of the c-axis, at room and significantly higher temperatures is shown. Spin centers in SiC, where optically induced spin alignment occurs, have a unique system of spin levels in a magnetic field, caused by the interaction of the fine structure and hyperfine interaction with the 29Si nuclei. There is a wide range of level anticrossings (LACs) resulting in an extremely strong change in the photoluminescence intensity at LAC. The dependence of the LAC spectrum on the orientation of the external magnetic field is also observed. The proposed magnetometer is based on the compensation of the external magnetic field at the position of the optical excitation spot of the confocal microscope. The sensitivity to a constant magnetic field for the z-component of the magnetic field (Bz) is better than 0.1μT/Hz in the confocal volume at room temperature. The sensitivity of polar and azimuthal angle determination depends on the sensitivity of the perpendicular component of the magnetic field, which is better than ∼0.01mT/Hz in the range from −0.4 to 0.4 mT.