Magnetic Resonance Express Analysis and Control of NV- Diamond Wafers for Quantum Technologies

Magnetic resonance methods for express analysis and control of diamond wafers with NV- centers for quantum technologies were developed. The scanning NV- -based ODMR spectrometer was built to analyze NV- local concentration, coherent properties, stress/strain, nitrogen content, electron-nuclear interactions in diamond wafers for quantum technologies. As an example, a 3D image of the ODMR and PL maps was presented for a non-uniform distribution of NV- centers in a diamond wafer, which had several growth zones with significantly different concentrations of nitrogen. The local stress/strain map was obtained by measuring the splitting of the ODMR line in zero magnetic field at room temperature. The double ODMR line is a consequence of the stress-induced splitting of the doublet with projections M-S = + 1 and M-S = - 1 in the ground triplet state of the NV- center. Local concentration of nitrogen donors (in EPR literature it is designated as N or P1 centers) was estimated from the ratio of the intensity of satellites caused by interaction with nitrogen donors and the central line of ODMR. The central line has a 2E split into two overlapping lines, the intensity of one of the lines is selected. The spectrometer is also designed to perform pulsed measurements of Rabi oscillations, spin-lattice and spin-spin relaxation times at wafer points isolated by focused laser excitation. A new option for using a spectrometer was introduced for measuring the ODMR of NV- centers in a linearly polarized light, which allowed to distinguish PL for centers of a certain orientation and suppress the PL from others.