All-Optical dc Nanotesla Magnetometry Using Silicon Vacancy Fine Structure in Isotopically Purified Silicon Carbide

• Published in: Physical review. X 2016-07, Vol.6 (3), p.031014, Article 031014
• Main Authors: Simin, D., Soltamov, V. A., Poshakinskiy, A. V., Anisimov, A. N., Babunts, R. A., Tolmachev, D. O., Mokhov, E. N., Trupke, M., Tarasenko, S. A., Sperlich, A., Baranov, P. G., Dyakonov, V., Astakhov, G. V.
• Format: Article
• Language: English
• Subjects: Color centers; Defects; Fine structure; Geophysics; High temperature; Magnetic fields; Magnetic measurement; Magnetic resonance; Nanotechnology; Photoluminescence; Quantum dots; Radio frequency; Robustness; Room temperature; Silicon carbide; Symmetry; Trapping; Vacancies; Waveguides
• ISSN: 2160-3308; 2160-3308
• DOI: 10.1103/PhysRevX.6.031014

We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-SiC28 ) and reveal not yet considered terms in the spin Hamiltonian, originated from the trigonal pyramidal symmetry of this spin-3/2 color center. These terms give rise to additional spin transitions, which would be otherwise forbidden, and lead to a level anticrossing in an external magnetic field. We observe a sharp variation of the photoluminescence intensity in the vicinity of this level anticrossing, which can be used for a purely all-optical sensing of the magnetic field. We achieve dc magnetic field sensitivity better than 100nT/Hz within a volume of 3×10−7mm3 at room temperature and demonstrate that this contactless method is robust at high temperatures up to at least 500 K. As our approach does not require application of radio-frequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3mm3 , the projection noise limit is below 100fT/Hz .