Spin-Light Coherence for Single-Spin Measurement and Control in Diamond

Dressing-Up Diamond Defects The spin states of nitrogen vacancy defects in diamond are being explored as information carriers and memories in quantum information systems. Their long lifetimes, fast manipulation rates, and the ability to couple them to adjacent electronic and nuclear spins provide the necessary properties for implementation in solid-state quantum networks. To date, however, the readout of the spin state via photoluminescence, either directly or indirectly, results in the destruction of the spin state. Buckley et al. (p. 1212, published online 14 October; see the Perspective by Milburn) have formed a light-matter hybrid state in which the spin interacts with laser light to form a polariton state. This hybrid state can be optically probed to produce a nondestructive measurement and manipulation technique for the spin state of the nitrogen-vacancy center. Optical pulses were used to nondestructively probe and manipulate the spin state of nitrogen vacancy defects in diamond. The exceptional spin coherence of nitrogen-vacancy centers in diamond motivates their function in emerging quantum technologies. Traditionally, the spin state of individual centers is measured optically and destructively. We demonstrate dispersive, single-spin coupling to light for both nondestructive spin measurement, through the Faraday effect, and coherent spin manipulation, through the optical Stark effect. These interactions can enable the coherent exchange of quantum information between single nitrogen-vacancy spins and light, facilitating coherent measurement, control, and entanglement that is scalable over large distances.