MIT researchers have developed a new, ultrasensitive magnetic-field detector1 that is 1,000 times more energy-efficient than its predecessors2. It could lead to miniaturized, battery-powered devices for medical and materials imaging, contraband3 detection, and even geological exploration. Magnetic-field detectors4, or magnetometers, are already used for all those applications. But existing technologies have drawbacks: Some rely on gas-filled chambers5; others work only in narrow frequency bands, limiting their utility.Synthetic6 diamonds with nitrogen vacancies7 -- defects that are extremely sensitive to magnetic fields -- have long held promise as the basis for efficient, portable magnetometers. A diamond chip about one-twentieth the size of a thumbnail could contain trillions of nitrogen vacancies, each capable of performing its own magnetic-field measurement.The problem has been aggregating8 all those measurements. Probing a nitrogen vacancy9 requires zapping it with laser light, which it absorbs and re-emits. The intensity10 of the emitted light carries information about the vacancys magnetic state.In the past, only a small fraction of the pump light was used to excite a small fraction of the NVs, says Dirk Englund, the Jamieson Career Development Assistant Professor in Electrical Engineering and Computer Science and one of the designers of the new device. We make use of almost all the pump light to measure almost all of the NVs.The MIT researchers report their new device in the latest issue of Nature Physics. First author on the paper is Hannah Clevenson, a graduate student in electrical engineering who is advised by senior authors Englund and Danielle Braje, a physicist11 at MIT Lincoln Laboratory. Theyre joined by Englunds students Matthew Trusheim and Carson Teale and by Tim Schrder, a postdoc in MITs Research Laboratory of Electronics.
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1 detector n.发觉者，探测器 参考例句： The detector is housed in a streamlined cylindrical container.探测器安装在流线型圆柱形容器内。 Please walk through the metal detector.请走过金属测试器。
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