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Register a new userThe nitrogen-vacancy center in diamond re-visited
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Symmetry considerations are used in presenting a model of the electronic structure and the associated dynamics of the nitrogen-vacancy center in diamond. The model accounts for the occurrence of optically induced spin polarization, for the change of emission level with spin polarization and for new measurements of transient emission. The rate constants given are in variance to those reported previously.
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Optical and microwave double resonance techniques are used to obtain the excited state structure of single nitrogen-vacancy centers in diamond. The excited state is an orbital doublet and it is shown that it can be split and associated transition strengths varied by external electric fields and by strain. A group theoretical model is developed. It gives a good account of the observations and contributes to an improved understanding of the electronic structure of the center. The findings are important for quantum information processing and other applications of the center.
The nitrogen-vacancy (NV) colour centre in diamond is an important physical system for emergent quantum technologies, including quantum metrology, information processing and communications, as well as for various nanotechnologies, such as biological and sub-diffraction limit imaging, and for tests of entanglement in quantum mechanics. Given this array of existing and potential applications and the almost 50 years of NV research, one would expect that the physics of the centre is well understood, however, the study of the NV centre has proved challenging, with many early assertions now believed false and many remaining issues yet to be resolved. This review represents the first time that the key empirical and ab initio results have been extracted from the extensive NV literature and assembled into one consistent picture of the current understanding of the centre. As a result, the key unresolved issues concerning the NV centre are identified and the possible avenues for their resolution are examined.
The photophysics and charge state dynamics of the nitrogen vacancy (NV) center in diamond has been extensively investigated but is still not fully understood. In contrast to previous work, we find that NV$^{0}$ converts to NV$^{-}$ under excitation with low power near-infrared (1064 nm) light, resulting in $increased$ photoluminescence from the NV$^{-}$ state. We used a combination of spectral and time-resolved photoluminescence experiments and rate-equation modeling to conclude that NV$^{0}$ converts to NV$^{-}$ via absorption of 1064 nm photons from the valence band of diamond. We report fast quenching and recovery of the photoluminescence from $both$ charge states of the NV center under low power 1064 nm laser excitation, which has not been previously observed. We also find, using optically detected magnetic resonance experiments, that the charge transfer process mediated by the 1064 nm laser is spin-dependent.
Nitrogen-vacancy (NV) centers in diamond have attracted significant interest because of their excellent spin and optical characteristics for quantum information and metrology. To take advantage of the characteristics, the precise control of the orientation of the N-V axis in the lattice is essential. Here we show that the orientation of more than 99 % of the NV centers can be aligned along the [111]-axis by CVD homoepitaxial growth on (111)-substrates. We also discuss about mechanisms of the alignment. Our result enables a fourfold improvement in magnetic-field sensitivity and opens new avenues to the optimum design of NV center devices.
Photochromism in single nitrogen-vacancy optical centers in diamond is demonstrated. Time-resolved optical spectroscopy shows that intense irradiation at 514 nm switches the nitrogen-vacancy defects to the negative form. This defect state relaxes back to the neutral form under dark conditions. Temporal anticorrelation of photons emitted by the different charge states of the optical center unambiguously indicates that the nitrogen-vacancy defect accounts for both 575 nm and 638 nm emission bands. Possible mechanism of photochromism involving nitrogen donors is discussed.
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