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Register a new userTime-averaging within the excited state of the nitrogen-vacancy centre in diamond
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The emission intensity of diamond samples containing nitrogen-vacancy centres are measured as a function of magnetic field along a <111> direction for various temperatures. At low temperatures the responses are sample and stress dependent and can be modeled in terms of the previous understanding of the 3E excited state fine structure which is strain dependent. At room temperature the responses are largely sample and stress independent, and modeling involves invoking a strain independent excited state with a single zero field splitting of 1.42 GHz. The change in behaviour is attributed to a temperature dependent averaging process over the components of the excited state orbital doublet. It decouples orbit and spin and at high temperature the spin levels become independent of any orbit splitting. Thus the models can be reconciled and the parameters for low and high temperatures are shown to be consistent.
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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.
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 optical transition linewidth and emission polarization of single nitrogen-vacancy (NV) centers are measured from 5 K to room temperature. Inter-excited state population relaxation is shown to broaden the zero-phonon line and both the relaxation and linewidth are found to follow a T^5 dependence for T up to 100 K. This dependence indicates that the dynamic Jahn-Teller effect is the dominant dephasing mechanism for the NV optical transitions at low temperatures.
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.
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.
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