sensor

JQI group uses diamond-based quantum sensors produce images of currents in graphene.

Optical fibers are ubiquitous, carrying light wherever it is needed. These glass tunnels are the high-speed railway of information transit, moving data at incredible speeds over tremendous distances. Fibers are also thin and flexible, so they can be immersed in many different environments, including the human body, where they are employed for illumination and imaging.Physicists use fibers, too, particularly those who study atomic physics and quantum information science. Aside from shuttling laser light around, fibers can be used to create light traps for super-chilled atoms. Captured atoms can interact more strongly with light, much more so than if they were moving freely. This rather artificial environment can be used to explore fundamental physics questions, such as how a single particle of light interacts with a single atom. But it may also assist with developing future hybrid atom-optical technologies.

In an arranged marriage of optics and mechanics, JQI-NIST physicists have created microscopic structural beams that have a variety of powerful uses when light strikes them. Able to operate in ordinary, room-temperature environments, yet exploiting some of the deepest principles of quantum physics, these optomechanical systems can act as inherently accurate thermometers, or conversely, as a type of optical shield that diverts heat. .Described in a pair of new papers in Science and Physical Review Letters, the potential applications include chip-based temperature sensors for electronics and biology that would never need to be adjusted since they rely on fundamental constants of nature; tiny refrigerators that can cool state-of-the-art microscope components for higher-quality images; and improved “metamaterials” that could allow researchers to manipulate light and sound in new ways.

The word “defect” doesn’t usually have a good connotation--often indicating failure. But for physicists, one common defect known as a nitrogen-vacancy center (NV center) has applications in both quantum information processing and ultra-sensitive magnetometry, the measurement of exceedingly faint magnetic fields. In an experiment, recently published in Science, JQI Fellow Vladimir Manucharyan and colleagues at Harvard University used NV centers in diamond to sense the properties of magnetic field noise tens of nanometers away from the silver samples.
Diamond, which is a vast array of carbon atoms, can contain a wide variety of defects. An NV center defect is formed when a nitrogen atom substitutes for a carbon atom and is adjacent...