Neil B. Manson

Nitrogen-vacancy center in diamond: Model of the electronic structure and associated dynamics

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.

Photon Echoes Produced by Switching Electric Fields

We demonstrate photon echoes in Eu3+:Y2SiO5 by controlling the inhomogeneous broadening of the Eu3+ 7F0<-->5D0 optical transition. This transition has a linear Stark shift, and we induce inhomogeneous broadening by applying an external electric field gradient. After optical excitation, reversing the polarity of the field rephases the ensemble, resulting in a photon echo. This is the first demonstration of such a photon echo, and its application as a quantum memory is discussed.

Excited-state spectroscopy of single NV defects in diamond using optically detected magnetic resonance.

Using pulsed optically detected magnetic resonance techniques, we directly probe electron-spin resonance transitions in the excited-state of single nitrogen-vacancy (NV) color centers in diamond. Unambiguous assignment of excited state fine structure is made, based on changes of NV defect photoluminescence lifetime. This study provides significant insight into the structure of the emitting 3 E excited state, which is invaluable for the development of diamond-based quantum information processing.

Low temperature studies of the excited-state structure of negatively charged nitrogen-vacancy color centers in diamond.

We report a study of the 3E excited-state structure of single negatively charged nitrogen-vacancy (NV) defects in diamond, combining resonant excitation at cryogenic temperatures and optically detected magnetic resonance. A theoretical model is developed and shows excellent agreement with experimental observations. In addition, we show that the two orbital branches associated with the 3E excited state are averaged when operating at room temperature. This study leads to an improved physical understanding of the NV defect electronic structure, which is invaluable for the development of diamond-based quantum information processing.

Two-laser spectral hole burning in a colour centre in diamond

Abstract Using two high-resolution lasers a short lived (∼1 ms) hole burning spectrum has been observed in the 637 nm zero-phonon transition associated with the nitrogen-vacancy centre in diamond. Amongst the prominent antiholes the ones at ±2.88 GHz coincide in frequency with that obtained in EPR for a spin-doublet-singlet splitting of a metastable 3 A state. In this work it is claimed that 3 A is the ground state and this is supported by the observation of temperature-dependent magnetic circular dichroism signals. Details in the hole burning spectrum are then interpreted in terms of a strain split 3 A→ 3 E transition.

Optically detected spin coherence of the diamond N-V centre in its triplet ground state

For the N-V centre in type Ib diamond the optical detection of spin coherence in the 3A state is reported. The 3A-state lifetime is studied as a function of the light intensity used for the optical excitation of the N-V centre by means of spin-locking experiments. The shortening of the lifetime at higher excitation intensities provides evidence for the previously proposed idea that the 3A state of the N-V centre is the ground state.

Spin-flip and spin-conserving optical transitions of the nitrogen-vacancy centre in diamond

We map out the first excited state sublevel structure of single nitrogen-vacancy (NV) colour centres in diamond. The excited state is an orbital doublet where one branch supports an efficient cycling transition, while the other can simultaneously support fully allowed optical Raman spin-flip transitions. This is crucial for the success of many recently proposed quantum information applications of the NV defects. We further find that an external electric field can be used to completely control the optical properties of a single centre. Finally, a group theoretical model is developed that explains the observations and provides good physical understanding of the excited state structure.

Infrared emission of the NV centre in diamond: Zeeman and uniaxial stress studies

An emission band in the infrared (IR) is shown to be associated with a transition within the negative nitrogen-vacancy centre in diamond. The band has a zero-phonon line at 1046?nm, and uniaxial stress and magnetic field measurements indicate that the emission is associated with a transition between 1E and 1A1 singlet levels. Inter-system crossing to these singlets causes the spin polarization that makes the NV- centre attractive for quantum information processing, and the IR emission band provides a new avenue for using the centre in such applications.

The negatively charged nitrogen-vacancy centre in diamond: the electronic solution

The negatively charged nitrogen-vacancy centre is a unique defect in diamond that possesses properties highly suited to many applications, including quantum information processing, quantum metrology and biolabelling. Although the unique properties of the centre have been extensively documented and utilized, a detailed understanding of the physics of the centre has not yet been achieved. Indeed, there persist a number of points of contention regarding the electronic structure of the centre, such as the ordering of the dark intermediate singlet states. Without a detailed model of the centres electronic structure, the understanding of the systems unique dynamical properties cannot effectively progress. In this work, the molecular model of the defect centre is fully developed to provide a self-consistent model of the complete electronic structure of the centre. The application of the model to describe the effects of electric, magnetic and strain interactions, as well as the variation of the centres fine structure with temperature, provides an invaluable tool to those studying the centre and a means of designing future empirical and ab initio studies of this important defect.

Electronic structure of the negatively charged silicon-vacancy center in diamond

The negatively-charged silicon-vacancy (SiV