Experimental Determination of the Dipole Orientation of Single Color Centers in Silicon Carbide

Divacancy defect spins in silicon carbide (SiC) are one of the promising candidates for quantum network and quantum information processing due to their attractive optical and spin properties. Although efforts have been made to investigate their properties and coherent manipulations, little is known about the properties of the optical dipole moment's orientation of these defects, which are critically important for fluorescence enhancement and quantum communication. In this study, we determined the dipole moment's orientation of single divacancy defects in 4H polytype SiC (4H-SiC) using tightly focused radially and azimuthally polarized laser beams through confocal microscopy. We can extract polar and azimuthal angles of the dipole moment compared with the theoretically calculated two-dimensional fluorescence intensity distributions. The polarization of photoluminescence of these different defects is measured and analyzed for comparison. These results are critical for the highly efficient nanostructure-coupled enhancement of emission and quantum communication where the dipole moment's orientation should be known.