The detection of single nuclear spins would be useful for fields ranging from basic science to quantum information technology. However, although sensing based on diamond defects and other methods have shown high sensitivity, they have not been capable of detecting single nuclear spins, and defect-based techniques further require strong defect-spin coupling. Here, we present the detection and identification of single and remote (13)C nuclear spins embedded in nuclear spin baths surrounding a single electron spin of a nitrogen-vacancy centre in diamond. We are able to amplify and detect the weak magnetic field noise (∼10 nT) from a single nuclear spin located ∼3 nm from the centre using dynamical decoupling control, and achieve a detectable hyperfine coupling strength as weak as ∼300 Hz. We also confirm the quantum nature of the coupling, and measure the spin-defect distance and the vector components of the nuclear field. The technique marks a step towards imaging, detecting and controlling nuclear spins in single molecules.

Spherical shaped Si quantum dots (QDs) embedded into the SiO 2 substrate are considered in the single sub-band effective mass approach. Electron and heavy hole sub-bands are taken into account.Nonparabolicity of the Si conduction band is described by the energy dependence of electron effective mass. Calculations of low-lying single electron and hole energy levels are performed. For small sizes QD (diameter 6 ≤ D nm) there is a strong confinement regime when the number of energy levels is restricted to several levels. The first order of the perturbation theory is used to calculate neutral exciton recombination energy taking into account the Coulomb force between electron and heavy hole. The PL exciton data are reproduced well by our model calculations. We also compare the results with those obtained within model [2]. For weak confinement regime (size ≥ D 10 nm), when the number of confinement levels is limited by several hundred, we considered the statistical properties of the electron confinement. Distribution function for the electron energy levels is calculated and results are discussed.