scholarly journals Optical magnetic detection of single-neuron action potentials using quantum defects in diamond

2016 ◽  
Vol 113 (49) ◽  
pp. 14133-14138 ◽  
Author(s):  
John F. Barry ◽  
Matthew J. Turner ◽  
Jennifer M. Schloss ◽  
David R. Glenn ◽  
Yuyu Song ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Action Potentials ◽  
Single Neuron ◽  
Magnetic Measurements ◽  
Field Vector ◽  
Nitrogen Vacancy ◽  
Label Free ◽  
Ambient Conditions ◽  
Close Proximity ◽  
Quantum Defects

Magnetic fields from neuronal action potentials (APs) pass largely unperturbed through biological tissue, allowing magnetic measurements of AP dynamics to be performed extracellularly or even outside intact organisms. To date, however, magnetic techniques for sensing neuronal activity have either operated at the macroscale with coarse spatial and/or temporal resolution—e.g., magnetic resonance imaging methods and magnetoencephalography—or been restricted to biophysics studies of excised neurons probed with cryogenic or bulky detectors that do not provide single-neuron spatial resolution and are not scalable to functional networks or intact organisms. Here, we show that AP magnetic sensing can be realized with both single-neuron sensitivity and intact organism applicability using optically probed nitrogen-vacancy (NV) quantum defects in diamond, operated under ambient conditions and with the NV diamond sensor in close proximity (∼10 µm) to the biological sample. We demonstrate this method for excised single neurons from marine worm and squid, and then exterior to intact, optically opaque marine worms for extended periods and with no observed adverse effect on the animal. NV diamond magnetometry is noninvasive and label-free and does not cause photodamage. The method provides precise measurement of AP waveforms from individual neurons, as well as magnetic field correlates of the AP conduction velocity, and directly determines the AP propagation direction through the inherent sensitivity of NVs to the associated AP magnetic field vector.

scholarly journals Detection of biological signals from a live mammalian muscle using an early stage diamond quantum sensor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James Luke Webb ◽  
Luca Troise ◽  
Nikolaj Winther Hansen ◽  
Christoffer Olsson ◽  
Adam M. Wojciechowski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Action Potentials ◽  
Early Stage ◽  
Digital Signal ◽  
Nitrogen Vacancy ◽  
Mammalian Tissue ◽  
Mouse Muscle ◽  
Processing Techniques ◽  
Electric Signals ◽  
Remotely Sense

AbstractThe ability to perform noninvasive and non-contact measurements of electric signals produced by action potentials is essential in biomedicine. A key method to do this is to remotely sense signals by the magnetic field they induce. Existing methods for magnetic field sensing of mammalian tissue, used in techniques such as magnetoencephalography of the brain, require cryogenically cooled superconducting detectors. These have many disadvantages in terms of high cost, flexibility and limited portability as well as poor spatial and temporal resolution. In this work we demonstrate an alternative technique for detecting magnetic fields generated by the current from action potentials in living tissue using nitrogen vacancy centres in diamond. With 50 pT/$$\sqrt{\text {Hz}}$$ Hz sensitivity, we show the first measurements of magnetic sensing from mammalian tissue with a diamond sensor using mouse muscle optogenetically activated with blue light. We show these proof of principle measurements can be performed in an ordinary, unshielded lab environment and that the signal can be easily recovered by digital signal processing techniques. Although as yet uncompetitive with probe electrophysiology in terms of sensitivity, we demonstrate the feasibility of sensing action potentials via magnetic field in mammals using a diamond quantum sensor, as a step towards microscopic imaging of electrical activity in a biological sample using nitrogen vacancy centres in diamond.

scholarly journals Some problems with old magnetic data processing

2020 ◽  
Vol 196 ◽  
pp. 02029
Author(s):  
Sergey Y. Khomutov ◽  
Manjula Lingala
Keyword(s):  
Magnetic Field ◽  
Scientific Community ◽  
Magnetic Measurements ◽  
Field Vector ◽  
Digital Data ◽  
Magnetic Data ◽  
Total Field ◽  
Analog To Digital ◽  
The Past ◽  
Lack Of Information

Continues magnetic measurements at the IKIR FEB RAS obser-vatories Magadan (MGD), Paratunka (PET), Yuzhno-Sakhalinsk (YSS), Cape Schmidt (CPS) and Khabarovsk (KHB) and CSIR-NGRI observatories Hyder-abad (HYB) and Choutuppal (CPL) have been started almost since their formation. A significant part of the results obtained is presented in the WDC and INTERMAGNET databases. However, a large amount of raw data remains un-processed and unavailable for using by scientific community. In the past few years, institutes has been making efforts to process and reprocess old magnetic data. Digital images of analog magnetograms of the Observatory Paratunka since 1967 were obtained and the possibility of their use for calculation hourly and minute values of magnetic field elements was evaluated. Old digital data that was available during the conversion from analog to digital magnetometers is processed. The main problem of processing or re-processing archived data is the lack of information (metadata) about the measurement conditions. First of all, these are the results of absolute observations, which are necessary to obtain the values of the elements of the total field vector. In this paper, some technologies are proposed that allow to use the data obtained during processing of analog magnetograms to adjust the digital magnetometers records. A signif-icant problem is the lack or inaccuracy of information about the temperature conditions in the variation pavilion, about magnetometers or support equipment maintenance or about works in and near the pavilions. As we accumulate the experience during the processing of old magnetic data, a “catalog” of noise and its typical images is formed. This makes it more reliable and efficient to identify and remove this noise from records.

scholarly journals Fiberized Diamond-Based Vector Magnetometers

2021 ◽  
Vol 2 ◽  
Author(s):  
Georgios Chatzidrosos ◽  
Joseph Shaji Rebeirro ◽  
Huijie Zheng ◽  
Muhib Omar ◽  
Andreas Brenneis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Sensitivity ◽  
Field Vector ◽  
Nitrogen Vacancy ◽  
Double Quantum ◽  
Optical Fibres ◽  
Vector Magnetic Field ◽  
Magnetic Field Sensors ◽  
Halbach Array ◽  
Quantum Transitions

We present two fiberized vector magnetic-field sensors, based on nitrogen-vacancy (NV) centers in diamond. The sensors feature sub-nT/Hz magnetic sensitivity. We use commercially available components to construct sensors with a small sensor size, high photon collection, and minimal sensor-sample distance. Both sensors are located at the end of optical fibres with the sensor-head freely accessible and robust under movement. These features make them ideal for mapping magnetic fields with high sensitivity and spatial resolution (≤ mm). As a demonstration we use one of the sensors to map the vector magnetic field inside the bore of a ≥100 mT Halbach array. The vector field sensing protocol translates microwave spectroscopy data addressing all diamonds axes and including double quantum transitions to a 3D magnetic field vector.

scholarly journals Nanometre-scale probing of spin waves using single electron spins

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Toeno van der Sar ◽  
Francesco Casola ◽  
Ronald Walsworth ◽  
Amir Yacoby
Keyword(s):  
Magnetic Field ◽  
Spin Wave ◽  
Analytical Description ◽  
Noise Spectrum ◽  
Real Space ◽  
Nitrogen Vacancy ◽  
Ambient Conditions ◽  
Longitudinal Magnetization ◽  
Correlated Electron ◽  
Spin Wave Excitations

Abstract Pushing the frontiers of condensed-matter magnetism requires the development of tools that provide real-space, few-nanometre-scale probing of correlated-electron magnetic excitations under ambient conditions. Here we present a practical approach to meet this challenge, using magnetometry based on single nitrogen-vacancy centres in diamond. We focus on spin-wave excitations in a ferromagnetic microdisc, and demonstrate local, quantitative and phase-sensitive detection of the spin-wave magnetic field at ∼50 nm from the disc. We map the magnetic-field dependence of spin-wave excitations by detecting the associated local reduction in the disc’s longitudinal magnetization. In addition, we characterize the spin–noise spectrum by nitrogen-vacancy spin relaxometry, finding excellent agreement with a general analytical description of the stray fields produced by spin–spin correlations in a 2D magnetic system. These complementary measurement modalities pave the way towards imaging the local excitations of systems such as ferromagnets and antiferromagnets, skyrmions, atomically assembled quantum magnets, and spin ice.

Magnetic Field Distribution in Aperture of TEM Horn Antenna for Close Proximity RF Immunity Test by Impulsive Excitation Wave

2020 ◽  
Vol 140 (12) ◽  
pp. 601-602
Author(s):  
Gen Kawakami ◽  
Ken Kawamata ◽  
Shinobu Ishigami ◽  
Takeshi Ishida ◽  
Katsushige Harima ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Horn Antenna ◽  
Magnetic Field Distribution ◽  
Excitation Wave ◽  
Impulsive Excitation ◽  
Close Proximity ◽  
Tem Horn

scholarly journals Room-temperature control and electrical readout of individual nitrogen-vacancy nuclear spins

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michal Gulka ◽  
Daniel Wirtitsch ◽  
Viktor Ivády ◽  
Jelle Vodnik ◽  
Jaroslav Hruby ◽  
...  
Keyword(s):  
Dipolar Interaction ◽  
Coherence Time ◽  
Wide Bandgap ◽  
Nitrogen Vacancy ◽  
Ambient Conditions ◽  
Nuclear Spins ◽  
Quantum Device ◽  
Nanoscale Electronics ◽  
Quantum Processor ◽  
Processor Unit

AbstractNuclear spins in semiconductors are leading candidates for future quantum technologies, including quantum computation, communication, and sensing. Nuclear spins in diamond are particularly attractive due to their long coherence time. With the nitrogen-vacancy (NV) centre, such nuclear qubits benefit from an auxiliary electronic qubit, which, at cryogenic temperatures, enables probabilistic entanglement mediated optically by photonic links. Here, we demonstrate a concept of a microelectronic quantum device at ambient conditions using diamond as wide bandgap semiconductor. The basic quantum processor unit – a single 14N nuclear spin coupled to the NV electron – is read photoelectrically and thus operates in a manner compatible with nanoscale electronics. The underlying theory provides the key ingredients for photoelectric quantum gate operations and readout of nuclear qubit registers. This demonstration is, therefore, a step towards diamond quantum devices with a readout area limited by inter-electrode distance rather than by the diffraction limit. Such scalability could enable the development of electronic quantum processors based on the dipolar interaction of spin-qubits placed at nanoscopic proximity.

scholarly journals Consideration of Magnetic Measurements for Characterisation of Ferrite–Martensite Commercial Dual-Phase (DP) Steel and Basis for Optimisation of the Operating Magnetic Field for Open Loop Deployable Sensors

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 490
Author(s):  
Mohsen Aghadavoudi Jolfaei ◽  
Lei Zhou ◽  
Claire Davis
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Initial Permeability ◽  
Open Loop ◽  
Dual Phase ◽  
Dp Steel ◽  
Ferrite Fraction ◽  
Lift Off ◽  
Steel Properties

The magnetic properties of commercial dual-phase (DP) steels (DP600, DP800 and DP1000 grades) were evaluated using initial permeability, incremental permeability and coercivity and correlated with the key microstructural differences between the grades. The ferrite grain sizes and ferrite fractions have been compared with the magnetic parameters obtained from minor and major magnetisation loops within each DP grade. It has been revealed that the incremental permeability increases with the applied magnetic field amplitude to reach a peak and then drops at a higher magnetic field, with the values being different for the three DP grades at a lower field and converging to a similar permeability value at the high field. The effects of ferrite grain size and phase fraction on the incremental permeability are considered, and it has been shown that the influence of ferrite grain boundaries on magnetic permeability is more dominant than the effect of ferrite fraction in commercial DP steel samples. An analysis of the correlation between coercivity and initial permeability with tensile strength shows that the initial permeability provides a slightly better prediction of strength for the steels examined, which is believed to be due to the fact that a combination of reversible and irreversible domain components affect the coercivity value, while the initial permeability is predominantly affected by reversible domain movements. Based on the trend between incremental permeability and applied magnetic field and the commercial EM sensor (EMspec) operating parameters, the effect of lift-off and hence magnetic field strength on the sensitivity to DP steel properties can be assessed.

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