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.
Significance
Quantum coherence has a fundamentally different origin for nonidentical and identical particles since for the latter a unique contribution exists due to indistinguishability. Here we experimentally show how to exploit, in a controllable fashion, the contribution to quantum coherence stemming from spatial indistinguishability. Our experiment also directly proves, on the same footing, the different role of particle statistics (bosons or fermions) in supplying coherence-enabled advantage for quantum metrology. Ultimately, our results provide insights toward viable quantum-enhanced technologies based on tunable indistinguishability of identical building blocks.
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