Optical Spin Initialization of Nitrogen Vacancy Centers in a 28Si-Enriched 6H-SiC Crystal for Quantum Technologies

High-spin defect centers in crystal matrices are used in quantum computing technologies, highly sensitive sensors, and single-photon sources. In this work, optically active nitrogen-vacancy color centers NV^– in a ²⁸Si-enriched (nuclear spin \(I = 0\)) 6H-²⁸SiC crystal have been studied using the photoinduced (\(\lambda \) = 980 nm) high-frequency (94 GHz, 3.4 T) pulsed electron paramagnetic resonance method at a temperature of \(T = 150{\kern 1pt} \) K. Three structurally nonequivalent types of NV^– centers with axial symmetry have been identified and their spectroscopic parameters have been determined. Long spin–lattice, \({{T}_{1}} = 1.3{\kern 1pt} \) ms, and spin–spin, \({{T}_{2}} = 59{\kern 1pt} \) μs, ensemble relaxation times of NV^– centers with extremely narrow (450 kHz) absorption lines allow highly selective excitation of resonant transitions between sublevels \(({{m}_{I}})\) caused by the weak hyperfine interaction \((A \approx 1{\kern 1pt} \) MHz) with ¹⁴N \((I = 1)\) nuclei for the quantum manipulation of the electron spin magnetization.