Read-out of single spins by optical spectroscopy

Abstract

We review recent experiments on optical detection and manipulation of spin states ofimpurity centres in a solid. This research topic is of particular interest because of possibleapplications of the single-spin read-out technique in solid state quantum computing. Theexperimental background of optical detection of single quantum systems in solids isintroduced. The interaction of an impurity centre with an excitation field is analysed interms of optical Bloch equations. Recent experiments on the electron spin resonance ofsingle organic molecules and paramagnetic defect centres in diamonds are presented. Weshow how the spin state of the nitrogen–vacancy paramagnetic defect in diamond can beread out optically. Pulsed electron spin resonance of the single paramagnetic defect centrein diamond is discussed.