A nitrogen vacancy center in diamond was studied as a solid state spin system realizing quantum information processing. In order to make such a system work as a qubit or a quantum memory, it was essential to have a full knowledge of interactions between the spins. Focusing on the properties of the nitrogen vacancy center, of which the electron spin was experimentally accessible and could be transferred to a single nuclear spin, dynamics and interactions between the single spins could be known to the full extent. The aim was to measure a change of state of the single nuclear spin upon interaction with single nitrogen vacancy electron spin within a short time interval. It corresponded to the weak measurement initiated by Aharonov et al., and through such a measurement the hyperfine interaction between the nitrogen vacancy electron spin and the nuclear spin could be determined. As a first step towards such an experimental application of the weak measurement scheme, the detection of single nitrogen vacancy centers via confocal laser microscopy and measurement of the second-order autocorrelation function were carried out. An optically detected magnetic resonance was used to manipulate and read out the electron spin state and evaluate the static magnetic field applied at the single nitrogen vacancy center on the basis of the obtained optically detected magnetic resonance spectra.

Detection and Manipulation of Single Spin of Nitrogen Vacancy Center in Diamond Toward Application of Weak Measurement. S.Kagami, Y.Shikano, K.Asahi: Physica E, 2011, 43[3], 761-5