Cover Image Credits

An apparatus for measuring and manipulating light from a fluorescent defect in a diamond. In the cover photo, a diamond is being irradiated by a 532-nm (green) laser n order to excite electrons in a site that has a nitrogen atom plus a vacancy. The resulting fluorescence is extraordinarily sensitive to tiny magnetic fields, including those from adjacent magnetic nuclei. Also evident in the photo is a loop antenna for microwave excitation and a water-cooled magnet, which surrounds the objective. This technology will fundamentally change experimental geochemistry (see article by Casey and others, p. 533–545). Photo by Zhipan Wang, UC Davis.