arXiv:1701.06838 · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE
Level anti-crossing magnetometry with color centers in diamond
Huijie Zheng, Georgios Chatzidrosos, Arne Wickenbrock, Lykourgos Bougas, Reinis Lazda, Andris Bērziņš, F. Gahbauer, Marcis P. Auzinsh, R. Ferber, Dmitry Budker
Recent developments in magnetic field sensing with negatively charged nitrogen-vacancy centers (NV) in diamond employ magnetic-field (MF) dependent features in the photoluminescence (PL) and eliminate the need for microwaves (MW). Here, we study two approaches towards improving the magnetometric sensitivity using the ground-state level anti-crossing (GSLAC) feature of the NV center at a background MF of 102.4 mT. Following the first approach, we investigate the feature parameters for precise alignment in a dilute diamond sample; the second approach extends the sensing protocol into absorption via detection of the GSLAC in the diamond transmission of a 1042nm laser beam. This leads to an increase of GSLAC contrast and results in a magnetometer with a sensitivity of 0.45 nT/√Hz and a photon shot-noise limited sensitivity of 12.2 pT/√Hz.
Recent developments in magnetic field sensing with negatively charged nitrogen-vacancy centers (NV) in diamond employ magnetic-field (MF) dependent features in the photoluminescence (PL) and eliminate the need for microwaves (MW). Here, we study two approaches towards improving the magnetometric sensitivity using the ground-state level anti-crossing (GSLAC) feature of the NV center at a background MF of 102.4 mT. Following the first approach, we investigate the feature parameters for precise alignment in a dilute diamond sample; the second approach extends the sensing protocol into absorption via detection of the GSLAC in the diamond transmission of a 1042nm laser beam. This leads to an increase of GSLAC contrast and results in a magnetometer with a sensitivity of 0.45 nT/√Hz and a photon shot-noise limited sensitivity of 12.2 pT/√Hz.
The nitrogen-vacancy center (NV center) in diamond at magnetic fields corresponding to the ground-state level anticrossing (GSLAC) region gives rise to rich photoluminescence (PL) signals due to the vanishing energy gap between the electron spin states, which enables for a broad variety of environmental couplings to have an effect on the NV center's luminescence. Previous works have addressed several aspects of the GSLAC photoluminescence, however, a comprehensive analysis of the GSLAC signature of NV ensembles in different spin environments at various external fields is missing. Here we employ a combination of experiments and recently developed numerical methods to investigate in detail the effects of transverse electric and magnetic fields, strain, P1 centers, NV centers, and the 13C nuclear spins on the GSLAC photoluminescence. Our comprehensive analysis provides a solid ground for advancing various microwave-free applications at the GSLAC, including but not limited to magnetometry, spectroscopy, dynamic nuclear polarization (DNP), and nuclear magnetic resonance (NMR) detection. We demonstrate that not only the most abundant 14NV center but the 15NV can also be utilized in such applications.
The nitrogen-vacancy center (NV center) in diamond at magnetic fields corresponding to the ground-state level anticrossing (GSLAC) region gives rise to rich photoluminescence (PL) signals due to the vanishing energy gap between the electron spin states, which enables for a broad variety of environmental couplings to have an effect on the NV center’s luminescence. Previous works have addressed several aspects of the GSLAC photoluminescence, however, a comprehensive analysis of the GSLAC signature of NV ensembles in different spin environments at various external fields is missing. Here we employ a combination of experiments and recently developed numerical methods to investigate in detail the effects of transverse electric and magnetic fields, strain, P1 centers, NV centers, and the 13C nuclear spins on the GSLAC photoluminescence. Our comprehensive analysis provides a solid ground for advancing various microwave-free applications at the GSLAC, including but not limited to magnetometry, spectroscopy, dynamic nuclear polarization (DNP), and nuclear magnetic resonance (NMR) detection. We demonstrate that not only the most abundant 14NV center but the 15NV can also be utilized in such applications.
The negatively charged nitrogen vacancy center in diamond is widely used for quantum sensing due to the sensitivity of the spin triplet in the electronic ground state to external perturbations such as strain and electromagnetic fields, which makes it an excellent probe for changes in these perturbations.The spin state can be measured through optically detected magnetic resonance, which is most commonly achieved by detecting the photoluminescence after exciting the spin-triplet transition.Recently, methods have been proposed and demonstrated that use the absorption of the infrared singlet transition at 1042 nm instead.These methods, however, require cryogenic temperatures or external cavities to enhance the absorption signal.Here, we report on our efforts to optimize the magnetometer sensitivity at room temperature and without cavities.We reach a sensitivity of 18 pT/ √ Hz, surpassing previously reported values, and a calculated shot-noise limit of 5 pT/ √ Hz .We also report on a defect that is native to diamond grown by chemical vapor deposition and thus absent in high-pressure high-temperature diamond, the excitation of which impacts the measured singlet absorption signal.
Nitrogen-vacancy (NV) centers in diamond have emerged as a robust room-temperature solid-state platform for weak magnetic field detection. Several NV-based magnetometers have been proposed in the past decades, but they still suffer from either low sensitivity or high power consumption. This is a challenge for sensors deployed in remote locations on Earth or in space that are not connected to the power grid. Although sunlight-driven quantum magnetometry, which does not rely on conventional energy sources, has been proposed as a possible solution, its sensitivity remains a limitation. Here, we present an impressive improvement in the sensitivity of the sunlight-driven NV-diamond quantum magnetometer. A crucial aspect of our approach involves leveraging the ground-state level anti-crossing properties of the NV centers, coupled with magnetic flux concentrators. This integration enables us to achieve a magnetic-field sensitivity of 26 pT/Hz in a laboratory environment and 49 pT/Hz when the magnetometer operates outdoors under sunlight. We also illustrate the promising potential of further improving the sensitivity to the subpicotesla level by using cutting-edge technologies. Furthermore, we reveal the capability of this quantum magnetometer as a receiver of extremely low-frequency magnetic signals and pave the way for communication applications. These advancements represent a significant leap toward attaining high-sensitivity and energy-efficient magnetic field sensing and expanding the range of possible applications for these environmentally sustainable quantum technologies.
Negatively charged boron vacancy (VB−) centers in hexagonal boron nitride (h-BN) have attracted wide-range interests owing to their van der Waals lattice and their potentials for in-situ quantum sensing. Here we propose and experimentally demonstrate an all-optical strategy for wide-field magnetometry based on VB− centers. This strategy exploits the magnetically sensitive ground-state level anti-crossing (GSLAC) of VB− centers, which induces a strong electron spin transition between mS=0 and mS=−1 states, enabling microwave-free magnetic field measurement. By monitoring the shift of GSLAC feature, the external magnetic field can be precisely determined. Using this technique, we demonstrate all-optical wide-field imaging of near-field DC magnetic field distribution from current-carrying circuits over an area of around 42 × 21 μm2. An estimated photon shot-noise-limited sensitivity of 67.1 μT/Hz is achieved for a single pixel, which is an approximately threefold improvement over the ODMR method, along with a spatial resolution of about 1 μm per pixel. Our approach expands the applicability of VB− centers in quantum sensing, paving the way for robust and convenient magnetometry under extreme conditions.
Nitrogen vacancy (NV) centers in diamond have attracted considerable recent interest for use in quantum sensing, promising increased sensitivity for applications ranging from geophysics to biomedicine. Conventional sensing schemes involve monitoring the change in red fluorescence from the NV center under green laser and microwave illumination. Due to the strong fluorescence background from emission in the NV triplet state and low relative contrast of any change in output, sensitivity is severely restricted by a high optical shot noise level. Here, we propose a means to avoid this issue, by using the change in green pump absorption through the diamond as part of a semiconductor external cavity laser run close to the lasing threshold. We show that theoretical sensitivity to the magnetic field on the pT/Hz level is possible using a diamond with an optimal density of NV centers. We discuss the physical requirements and limitations of the method, particularly the role of amplified spontaneous emission near threshold and explore realistic implementations using current technology.