Nanoscale imaging magnetometry with diamond spins under ambient conditions

A type of natural impurity in diamond crystals, called a nitrogen-vacancy centre, has a unique, long-lived single electron spin state that can be controlled and detected optically. This property can be used to create 'spintronics' devices and has possible application in quantum information processing. Two groups this week describe the application of this technology to nanoscale magnetic resonance imaging. Maze et al. demonstrate magnetic sensing using coherent control of diamond spins. They show that in principle, precision measurements of nano-tesla magnetic fields are possible, corresponding roughly to the field of a single proton at a distance of 10 nm. Balasubramanian et al. demonstrate initial steps towards a sensitive, high-resolution imaging technique using diamond spins. They show that the location of single nitrogen-vacancy spins can be determined to 5-nm resolution. In an accompanying News & Views, Michael Romalis observes that a combination of these two techniques could lead to detection and imaging of individual nuclear spins, even the structure determination for a single molecule. And as both experiments were done at room temperature, biological applications of these methods can be anticipated.