We uncover the fine structure of a silicon vacancy in isotopically purified silicon carbide (4H-28SiC) and find extra 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 are 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 of 87 nT Hz−1/2 within a volume of 3×10−7 mm3 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 radiofrequency fields, it is scalable to much larger volumes. For an optimized light-trapping waveguide of 3 mm3 the projection noise limit is below 100 fT Hz−1/2.
@article{arxiv.1511.04663,
title = {All-optical dc nanotesla magnetometry using silicon vacancy fine structure in isotopically purified silicon carbide},
author = {D. Simin and V. A. Soltamov and A. V. Poshakinskiy and A. N. Anisimov and R. A. Babunts and D. O. Tolmachev and E. N. Mokhov and M. Trupke and S. A. Tarasenko and A. Sperlich and P. G. Baranov and V. Dyakonov and G. V. Astakhov},
journal= {arXiv preprint arXiv:1511.04663},
year = {2016}
}
Comments
12 pages, 6 figures; additional experimental data and an extended theoretical analysis are added in the second version