81 research outputs found
The electron-phonon processes of the nitrogen-vacancy center in diamond
Applications of negatively charged nitrogen-vacancy center in diamond exploit
the center's unique optical and spin properties, which at ambient temperature,
are predominately governed by electron-phonon interactions. Here, we
investigate these interactions at ambient and elevated temperatures by
observing the motional narrowing of the center's excited state spin resonances.
We determine that the center's Jahn-Teller dynamics are much slower than
currently believed and identify the vital role of symmetric phonon modes. Our
results have pronounced implications for center's diverse applications
(including quantum technology) and for understanding its fundamental
properties.Comment: 5 pages, 4 figure
Singlet levels of the NV centre in diamond
The characteristic transition of the NV- centre at 637 nm is between
and triplet states. There are also
intermediate and singlet states, and the
infrared transition at 1042 nm between these singlets is studied here using
uniaxial stress. The stress shift and splitting parameters are determined, and
the physical interaction giving rise to the parameters is considered within the
accepted electronic model of the centre. It is established that this
interaction for the infrared transition is due to a modification of
electron-electron Coulomb repulsion interaction. This is in contrast to the
visible 637 nm transition where shifts and splittings arise from modification
to the one-electron Coulomb interaction. It is also established that a dynamic
Jahn-Teller interaction is associated with the singlet state,
which gives rise to a vibronic level 115 above the
electronic state. Arguments associated with this level are
used to provide experimental confirmation that the is the
upper singlet level and is the lower singlet level.Comment: 19 pages, 6 figure
Observation of the dynamic Jahn-Teller effect in the excited states of nitrogen-vacancy centers in diamond
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
Optical patterning of trapped charge in nitrogen-doped diamond
The nitrogen-vacancy (NV) centre in diamond is emerging as a promising
platform for solid-state quantum information processing and nanoscale
metrology. Of interest in these applications is the manipulation of the NV
charge, which can be attained by optical excitation. Here we use two-color
optical microscopy to investigate the dynamics of NV photo-ionization, charge
diffusion, and trapping in type-1b diamond. We combine fixed-point laser
excitation and scanning fluorescence imaging to locally alter the concentration
of negatively charged NVs, and to subsequently probe the corresponding
redistribution of charge. We uncover the formation of spatial patterns of
trapped charge, which we qualitatively reproduce via a model of the interplay
between photo-excited carriers and atomic defects. Further, by using the NV as
a probe, we map the relative fraction of positively charged nitrogen upon
localized optical excitation. These observations may prove important to
transporting quantum information between NVs or to developing
three-dimensional, charge-based memories
Perfect alignment and preferential orientation of nitrogen-vacancy centers during CVD growth of diamond on (111) surfaces
Synthetic diamond production is key to the development of quantum metrology
and quantum information applications of diamond. The major quantum sensor and
qubit candidate in diamond is the nitrogen-vacancy (NV) color center. This
lattice defect comes in four different crystallographic orientations leading to
an intrinsic inhomogeneity among NV centers that is undesirable in some
applications. Here, we report a microwave plasma-assisted chemical vapor
decomposition (MPCVD) diamond growth technique on (111)-oriented substrates
that yields perfect alignment () of as-grown NV centers along a single
crystallographic direction. In addition, clear evidence is found that the
majority () of the aligned NV centers were formed by the nitrogen
being first included in the (111) growth surface and then followed by the
formation of a neighboring vacancy on top. The achieved homogeneity of the
grown NV centers will tremendously benefit quantum information and metrology
applications.Comment: 6 pages, 4 figures, changes to previous version: added
acknowledgemen
Spin coherent quantum transport of electrons between defects in diamond
The nitrogen-vacancy color center in diamond has rapidly emerged as an
important solid-state system for quantum information processing. While
individual spin registers have been used to implement small-scale diamond
quantum computing, the realization of a large-scale device requires development
of an on-chip quantum bus for transporting information between distant qubits.
Here we propose a method for coherent quantum transport of an electron and its
spin state between distant NV centers. Transport is achieved by the
implementation of spatial stimulated adiabatic Raman passage through the
optical control of the NV center charge states and the confined conduction
states of a diamond nanostructure. Our models show that for two NV centers in a
diamond nanowire, high fidelity transport can be achieved over distances of
order hundreds of nanometres in timescales of order hundreds of nanoseconds.
Spatial adiabatic passage is therefore a promising option for realizing an
on-chip spin quantum bus
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