Nanotesla sensitivity magnetic field sensing using a compact diamond nitrogen-vacancy magnetometer

Abstract

Solid state sensors utilizing diamond nitrogen-vacancy (NV) centers are a promising sensing platform that can provide high sensitivity and spatial resolution at high precision. Such sensors have been realized in bulky laboratory-based forms; however, practical applications demand a miniaturized, portable sensor that can function in a wide range of environmental conditions. Here, we demonstrate such a diamond NV magnetic field sensor. The sensor head fits inside a 11×7×7 cm3 3D-printed box and exhibits sub-10 nT/Hz sensitivity over a 125 Hz bandwidth. We achieve efficient fluorescence collection using an optical filter and diode in contact with the diamond, which is cut at the Brewster angle to maximize the coupling of 532 nm pump light. We discuss the potential of this flexible approach to achieve sub-nT/Hz shot noise limited sensitivity suitable for detection of a wide range of low-level magnetic fields, particularly those from electrical power systems and from biological sources.

Construction and operation of a tabletop system for nanoscale magnetometry with single nitrogen-vacancy centers in diamond

“…By replacing bulky electronics with integrated circuits, portable NV magnetometers usable outside of the laboratory environment may be realized. [37][38][39] On the other hand, the use of scanning stages to resolve single NV centers means additional system complexity and size, even though we made an effort to keep the system compact by utilizing commercially available, off-the-shelf fiber optic components and optical cage system. Still limited to the laboratory use, our system is capable of working with single NV centers, and is fully fledged, in the sense that in principle many of state-of-the-art NMR experiments with single NV centers can be performed.…”

Benchmark for Synthesized Diamond Sensors Based on Isotopically Engineered Nitrogen‐Vacancy Spin Ensembles for Magnetometry Applications

“…[9] Transferring these sensors to state-of-the-art quantum technology requires the reproducible fabrication of NV centers with high spatial precision and reliable spin coherence properties. [10,11] Nitrogen doping during chemical vapor deposition (CVD) diamond growth is one of the facile means of fabricating thin layers of shallow NV ensembles. [12] It is essential for ultra-sensitive nanoscale magnetometry that shallow NV centers are engineered to be placed in a close proximity to the sensing target.…”

“…The latter is known to artificially prolong the coherence time since only the influence and not the spin bath itself is reduced, which is desired from a material scientist's point of view. The XY8 sequence is chosen The growth temperature is labeled as Temp, the nitrogen gas concentration during the growth in respect to hydrogen as N/H, the thickness of the buffer layer as d buffer , the one of the NV rich layer as d NV , the dephasing time measured by Ramsey sequence as T * 2 , the coherence time measured by Hahn echo as T 2 , the artificially prolonged coherence time by XY8 sequence with 128 -pulses as T XY 2 [8][9][10][11][12][13][14][15][16] , the NV density as n NV , the P1 density as n P1 , the overall nitrogen density measured by SIMS n N D , and the estimated volume normalized ac magnetic field sensitivity as V . The latter's estimation was performed using a pulsed detection scheme with a readout laser pulse of l = 300 ns, full spin contrast, and a count rate of a single NV center c R = 200 kcts s −1 as reported in ref.…”

Ultrasensitive Magnetic Field Sensors for Biomedical Applications

“…The geometries for and ((ii) and (iii)) are shown in panels (a) and (b) of Figure 10, respectively. A nitrogen vacancy center in diamond is a defect in the crystal lattice of diamond [157,158]. Such defects have an electronic structure consisting of two electrons from nitrogen, three electrons from carbon and one electron being captured from the lattice so the overall charge of the vacancy is negative.…”