A microfabricated fiber-integrated diamond magnetometer with ensemble nitrogen-vacancy centers

Miniaturization is a trend of development toward practical applications for diamond nitrogen-vacancy centers-based sensors. We demonstrate a compact diamond magnetic field sensor device using a standard microfabrication process. A single-crystal-diamond plate is embedded in a cavity formed with stacking of three silicon chips. Thermal compression bonding is implemented at silicon-silicon and diamond-silicon interfaces ensuring mechanical robustness. The specific construction volume for the essential sensor component is about 10 x 10 x 1.5 mm(3). By integrating a gradient index lens pigtailed fiber to the sensor device, 532-nm laser light and emitted fluorescence share a common path for excitation and detection. An omega-shaped transmission line for applied microwave power is fabricated directly on the surface of diamond. The integrated sensor device exhibits an optimized sensitivity of 2.03 nT.Hz(-1/2) and over twofold enhancement of fluorescence collection efficiency compared to bare diamond. Such a sensor is utilized to measure a magnetic field change caused by switching a household electrical appliance.& nbsp;Published under an exclusive license by AIP Publishing.