1
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Albertova P, Gram M, Blaimer M, Bauer WR, Jakob PM, Nordbeck P. Rotary excitation of non-sinusoidal pulsed magnetic fields: Towards non-invasive direct detection of cardiac conduction. Magn Reson Med 2024; 92:1965-1979. [PMID: 38934418 DOI: 10.1002/mrm.30190] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 04/09/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024]
Abstract
PURPOSE There is a need for high resolution non-invasive imaging methods of physiologic magnetic fields. The purpose of this work is to develop a MRI detection approach for non-sinusoidal magnetic fields based on the rotary excitation (REX) mechanism which was previously successfully applied for the detection of oscillating magnetic fields in the sub-nT range. METHODS The new detection concept was examined by means of Bloch simulations, evaluating the interaction effect of spin-locked magnetization and low-frequency pulsed magnetic fields. The REX detection approach was validated under controlled conditions in phantom experiments at 3 T. Gaussian and sinc-shaped stimuli were investigated. In addition, the detection of artificial fields resembling a cardiac QRS complex, which is the most prominent peak visible on a magnetocardiogram, was tested. RESULTS Bloch simulations demonstrated that the REX method has a high sensitivity to pulsed fields in the resonance case, which is met when the spin-lock frequency coincides with a non-zero Fourier component of the stimulus field. In the experiments, we found that magnetic stimuli of different durations and waveforms can be distinguished by their characteristic REX response spectrum. The detected REX amplitude was proportional to the stimulus peak amplitude (R2 > 0.98) and the lowest field detection was 1 nT. Furthermore, the detection of QRS-like fields with varying QRS durations yielded significant results in a phantom setup (p < 0.001). CONCLUSION REX detection can be transferred to non-sinusoidal pulsed magnetic fields and could provide a non-invasive, quantitative tool for spatially resolved assessment of cardiac biomagnetism. Potential applications include the direct detection and characterization of cardiac conduction.
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Affiliation(s)
- Petra Albertova
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Maximilian Gram
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Martin Blaimer
- Fraunhofer Institute for Integrated Circuits IIS, Würzburg, Germany
| | | | | | - Peter Nordbeck
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
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2
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Cook H, Bezsudnova Y, Koponen LM, Jensen O, Barontini G, Kowalczyk AU. An optically pumped magnetic gradiometer for the detection of human biomagnetism. QUANTUM SCIENCE AND TECHNOLOGY 2024; 9:035016. [PMID: 38680502 PMCID: PMC11047143 DOI: 10.1088/2058-9565/ad3d81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/21/2024] [Accepted: 04/11/2024] [Indexed: 05/01/2024]
Abstract
We realise an intrinsic optically pumped magnetic gradiometer based on non-linear magneto-optical rotation. We show that our sensor can reach a gradiometric sensitivity of 18 fT cm - 1 Hz - 1 and can reject common mode homogeneous magnetic field noise with up to 30 dB attenuation. We demonstrate that our magnetic field gradiometer is sufficiently sensitive and resilient to be employed in biomagnetic applications. In particular, we are able to record the auditory evoked response of the human brain, and to perform real-time magnetocardiography in the presence of external magnetic field disturbances. Our gradiometer provides complementary capabilities in human biomagnetic sensing to optically pumped magnetometers, and opens new avenues in the detection of human biomagnetism.
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Affiliation(s)
- Harry Cook
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Yulia Bezsudnova
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Lari M Koponen
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2SA, United Kingdom
| | - Ole Jensen
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2SA, United Kingdom
| | - Giovanni Barontini
- School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2SA, United Kingdom
| | - Anna U Kowalczyk
- Centre for Human Brain Health, School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2SA, United Kingdom
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3
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Jia J, Novikov V, Brasil TB, Zeuthen E, Müller JH, Polzik ES. Acoustic frequency atomic spin oscillator in the quantum regime. Nat Commun 2023; 14:6396. [PMID: 37828042 PMCID: PMC10570288 DOI: 10.1038/s41467-023-42059-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023] Open
Abstract
Quantum noise reduction and entanglement-enhanced sensing in the acoustic frequency range is an outstanding challenge relevant for a number of applications including magnetometry and broadband noise reduction in gravitational wave detectors. Here we experimentally demonstrate quantum behavior of a macroscopic atomic spin oscillator in the acoustic frequency range. Quantum back-action of the spin measurement, ponderomotive squeezing of light, and virtual spring softening are observed at oscillation frequencies down to the sub-kHz range. Quantum noise sources characteristic of spin oscillators operating in the near-DC frequency range are identified and means for their mitigation are presented.
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Affiliation(s)
- Jun Jia
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Valeriy Novikov
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
- Russian Quantum Center, Skolkovo, Moscow, Russia
| | | | - Emil Zeuthen
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | | | - Eugene S Polzik
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
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4
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Bao G, Chen J, Wang R, Chen LQ, Zhang W. SERF-like magnetometry in room-temperature environment. OPTICS EXPRESS 2023; 31:34779-34788. [PMID: 37859226 DOI: 10.1364/oe.500875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 09/18/2023] [Indexed: 10/21/2023]
Abstract
We demonstrate an atomic magnetometry using amplitude-modulated pumping and hyperfine repumping techniques in a paraffin-coated cell. By exploiting the constructive interference between spins polarized by the pump beam and an additional repump beam, we observe a three-fold increase in the amplitude of magnetic resonance, along with a reduction in linewidth by approximately two times. The implementation of the repump beam effectively narrows the linewidth, demonstrating successful suppression of spin-exchange relaxation. This reduction in relaxation rate, combined with the enhanced signal, significantly improves the sensitivity of the magnetometer. Consequently, our technique offers a promising approach for achieving SERF-like magnetometry with sub-fT-level sensitivity in Earth-field range and room-temperature environment.
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5
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Brisinda D, Fenici P, Fenici R. Clinical magnetocardiography: the unshielded bet-past, present, and future. Front Cardiovasc Med 2023; 10:1232882. [PMID: 37636301 PMCID: PMC10448194 DOI: 10.3389/fcvm.2023.1232882] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/23/2023] [Indexed: 08/29/2023] Open
Abstract
Magnetocardiography (MCG), which is nowadays 60 years old, has not yet been fully accepted as a clinical tool. Nevertheless, a large body of research and several clinical trials have demonstrated its reliability in providing additional diagnostic electrophysiological information if compared with conventional non-invasive electrocardiographic methods. Since the beginning, one major objective difficulty has been the need to clean the weak cardiac magnetic signals from the much higher environmental noise, especially that of urban and hospital environments. The obvious solution to record the magnetocardiogram in highly performant magnetically shielded rooms has provided the ideal setup for decades of research demonstrating the diagnostic potential of this technology. However, only a few clinical institutions have had the resources to install and run routinely such highly expensive and technically demanding systems. Therefore, increasing attempts have been made to develop cheaper alternatives to improve the magnetic signal-to-noise ratio allowing MCG in unshielded hospital environments. In this article, the most relevant milestones in the MCG's journey are reviewed, addressing the possible reasons beyond the currently long-lasting difficulty to reach a clinical breakthrough and leveraging the authors' personal experience since the early 1980s attempting to finally bring MCG to the patient's bedside for many years thus far. Their nearly four decades of foundational experimental and clinical research between shielded and unshielded solutions are summarized and referenced, following the original vision that MCG had to be intended as an unrivaled method for contactless assessment of the cardiac electrophysiology and as an advanced method for non-invasive electroanatomical imaging, through multimodal integration with other non-fluoroscopic imaging techniques. Whereas all the above accounts for the past, with the available innovative sensors and more affordable active shielding technologies, the present demonstrates that several novel systems have been developed and tested in multicenter clinical trials adopting both shielded and unshielded MCG built-in hospital environments. The future of MCG will mostly be dependent on the results from the ongoing progress in novel sensor technology, which is relatively soon foreseen to provide multiple alternatives for the construction of more compact, affordable, portable, and even wearable devices for unshielded MCG inside hospital environments and perhaps also for ambulatory patients.
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Affiliation(s)
- D. Brisinda
- Dipartimento Scienze dell'invecchiamento, ortopediche e reumatologiche, Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, Italy
- School of Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
- Biomagnetism and Clinical Physiology International Center (BACPIC), Rome, Italy
| | - P. Fenici
- School of Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
- Biomagnetism and Clinical Physiology International Center (BACPIC), Rome, Italy
| | - R. Fenici
- Biomagnetism and Clinical Physiology International Center (BACPIC), Rome, Italy
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6
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Wu S, Bao G, Guo J, Chen J, Du W, Shi M, Yang P, Chen L, Zhang W. Quantum magnetic gradiometer with entangled twin light beams. SCIENCE ADVANCES 2023; 9:eadg1760. [PMID: 37043567 PMCID: PMC10096575 DOI: 10.1126/sciadv.adg1760] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
In the past few decades, optical magnetometry has experienced remarkable development and reached to an outstanding sensitivity. For magnetometry based on optical readout of atomic ensemble, the fundamental limitation of sensitivity is restricted by spin projection noise and photon shot noise. Meanwhile, in practical applications, ambient magnetic noise also greatly limits the sensitivity. To achieve the best sensitivity, it is essential to find an efficacious way to eliminate the noises from different sources, simultaneously. Here, we demonstrate a quantum magnetic gradiometer with sub-shot-noise sensitivity using entangled twin beams with differential detection. The quantum enhancement spans a frequency range from 7 Hz to 6 MHz with maximum squeezing of 5.5 dB below the quantum noise limit. The sensitivity of gradiometer reaches 18 fT/cm[Formula: see text] at 20 Hz. Our study inspires future possibilities to use quantum-enhanced technology in developing sensitive magnetometry for practical applications in noisy and physically demanding environments.
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Affiliation(s)
- Shuhe Wu
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Guzhi Bao
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Jinxian Guo
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Jun Chen
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Wei Du
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Minwei Shi
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Peiyu Yang
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
| | - Liqing Chen
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
- State Key Laboratory of Precision Spectroscopy, Quantum Institute for Light and Atom, Department of Physics, East China Normal University, Shanghai 200062, China
| | - Weiping Zhang
- School of Physics and Astronomy, and Tsung-Dao Lee institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Branch, Hefei National Laboratory, Shanghai 201315, China
- Shanghai Research Center for Quantum Sciences, Shanghai 2013, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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7
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Aslam N, Zhou H, Urbach EK, Turner MJ, Walsworth RL, Lukin MD, Park H. Quantum sensors for biomedical applications. NATURE REVIEWS. PHYSICS 2023; 5:157-169. [PMID: 36776813 PMCID: PMC9896461 DOI: 10.1038/s42254-023-00558-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 05/09/2023]
Abstract
Quantum sensors are finding their way from laboratories to the real world, as witnessed by the increasing number of start-ups in this field. The atomic length scale of quantum sensors and their coherence properties enable unprecedented spatial resolution and sensitivity. Biomedical applications could benefit from these quantum technologies, but it is often difficult to evaluate the potential impact of the techniques. This Review sheds light on these questions, presenting the status of quantum sensing applications and discussing their path towards commercialization. The focus is on two promising quantum sensing platforms: optically pumped atomic magnetometers, and nitrogen-vacancy centres in diamond. The broad spectrum of biomedical applications is highlighted by four case studies ranging from brain imaging to single-cell spectroscopy.
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Affiliation(s)
- Nabeel Aslam
- Department of Physics, Harvard University, Cambridge, MA USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA USA
- Institute of Condensed Matter Physics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Hengyun Zhou
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Elana K. Urbach
- Department of Physics, Harvard University, Cambridge, MA USA
| | - Matthew J. Turner
- Quantum Technology Center, University of Maryland, College Park, MD USA
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD USA
| | - Ronald L. Walsworth
- Quantum Technology Center, University of Maryland, College Park, MD USA
- Department of Electrical and Computer Engineering, University of Maryland, College Park, MD USA
- Department of Physics, University of Maryland, College Park, MD USA
| | | | - Hongkun Park
- Department of Physics, Harvard University, Cambridge, MA USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA USA
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8
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Yan W, Ren X, Zhou M, Hu Z. Precision Magnetic Field Sensing with Dual Multi-Wave Atom Interferometer. SENSORS (BASEL, SWITZERLAND) 2022; 23:173. [PMID: 36616768 PMCID: PMC9823334 DOI: 10.3390/s23010173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Precision magnetic field measurement is widely used for practical applications, fundamental research, and medical purposes, etc. We propose a novel quantum magnetometer based on atoms' multi-wave (3-wave and 5-wave) Ramsey interference. Our design features high phase sensitivity and can be applied to in situ measurements of the magnetic field inside vacuum chambers. The final state detection is designed to be achieved by Raman's two-photon transition. The analytical solution for applicable interference fringe is presented. Fringe contrast decay due to atom temperature and magnetic field gradient is simulated to estimate reasonable experimental conditions. Sensitivity functions for phase noise and magnetic field noise in a multi-wave system are derived to estimate the noise level required to reach the expected resolution. The validity of the model, dual-channel features on bias estimation, and the quasi-non-destructive detection feature are discussed.
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9
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Rushton LM, Pyragius T, Meraki A, Elson L, Jensen K. Unshielded portable optically pumped magnetometer for the remote detection of conductive objects using eddy current measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:125103. [PMID: 36586912 DOI: 10.1063/5.0102402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/06/2022] [Indexed: 06/17/2023]
Abstract
Electrically conductive objects can be detected using the principle of electromagnetic induction, where a primary oscillating magnetic field induces eddy currents in the object, which in turn produce a secondary magnetic field that can be measured with a magnetometer. We have developed a portable radio-frequency optically pumped magnetometer (RF OPM) working in unshielded conditions with sub-pT/Hz magnetic field sensitivity when used for the detection of small oscillating magnetic fields, setting a new benchmark for the sensitivity of a portable RF OPM in unshielded conditions. Using this OPM, we have detected the induced magnetic field from aluminum disks with diameters as small as 1.5 cm and with the disks being ∼25 cm from both the excitation coil and the magnetometer. When used for eddy current detection, our magnetometer achieves a sensitivity of a 2-6 pT/Hz. We have also detected a moving aluminum disk using our RF OPM and analyzed the magnetometer signals, which depend on the position of the disk, illustrating the potential of high sensitivity RF OPMs for remote sensing applications.
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Affiliation(s)
- L M Rushton
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - T Pyragius
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - A Meraki
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - L Elson
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - K Jensen
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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10
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Campbell K, Wang YJ, Savukov I, Schwindt PDD, Jau YY, Shah V. Gradient Field Detection Using Interference of Stimulated Microwave Optical Sidebands. PHYSICAL REVIEW LETTERS 2022; 128:163602. [PMID: 35522487 DOI: 10.1103/physrevlett.128.163602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/27/2022] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
We demonstrate that stimulated microwave optical sideband generation using parametric frequency conversion can be utilized as a powerful technique for coherent state detection in atomic physics experiments. The technique has advantages over traditional absorption or polarization rotation-based measurements and enables the isolation of signal photons from probe photons. We outline a theoretical framework that accurately models sideband generation using a density matrix formalism. Using this technique, we demonstrate a novel intrinsic magnetic gradiometer that detects magnetic gradient fields between two spatially separated vapor cells by measuring the frequency of the beat note between sidebands generated within each cell. The sidebands are produced with high efficiency using parametric frequency conversion of a probe beam interacting with ^{87}Rb atoms in a coherent superposition of magnetically sensitive hyperfine ground states. Interference between the sidebands generates a low-frequency beat note whose frequency is determined by the magnetic field gradient between the two vapor cells. In contrast to traditional gradiometers the intermediate step of measuring the magnetic field experienced by the two vapor cells is unnecessary. We show that this technique can be readily implemented in a practical device by demonstrating a compact magnetic gradiometer sensor head with a sensitivity of 25 fT/cm/sqrt[Hz] with a 4.4 cm baseline, while operating in a noisy laboratory environment unshielded from Earth's field.
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Affiliation(s)
- Kaleb Campbell
- Sandia National Laboratory, 1515 Eubank SE, Albuquerque, New Mexico 87123, USA
- Center for Quantum Information and Control, Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Ying-Ju Wang
- QuSpin Inc, 331S 104th St. Unit 130, Louisville, Colorado 80027, USA
| | - Igor Savukov
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Peter D D Schwindt
- Sandia National Laboratory, 1515 Eubank SE, Albuquerque, New Mexico 87123, USA
| | - Yuan-Yu Jau
- Sandia National Laboratory, 1515 Eubank SE, Albuquerque, New Mexico 87123, USA
| | - Vishal Shah
- QuSpin Inc, 331S 104th St. Unit 130, Louisville, Colorado 80027, USA
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11
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Xing B, Lu J, Sun C, Yu T, Wu Y, Gao Y, Han B. Suppression of the magnetic noise response caused by elliptically polarized light in an optical rotation detection system. OPTICS EXPRESS 2022; 30:3854-3865. [PMID: 35209635 DOI: 10.1364/oe.449951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
We analyze and suppress the magnetic noise response in optical rotation detection system (ORDS) in atomic magnetometers in this study. Because of the imperfections of the optical elements, the probe light is actually elliptically polarized in ORDS, which can polarize the atom ensemble and cause the responses to the three-axis magnetic noise. We theoretically analyze the frequency responses to the magnetic noise, and prove that the responses are closely associated with the DC magnetic field. The values of the DC magnetic fields are calculated with special frequency points, called 'break points', in the transverse responses. We reveal the relationships between the DC magnetic field and the sensitivities of ORDS, and effectively suppress the magnetic noise responses with the residual magnetic field compensation. Finally, the sensitivity of ORDS is improved by approximately two times at 10-20 Hz.
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12
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Zhu M, Wang L, Guo J, Zhao X, Sun X, Ye C, Zhou X. Improvement in the signal amplitude and bandwidth of an optical atomic magnetometer via alignment-to-orientation conversion. OPTICS EXPRESS 2021; 29:28680-28691. [PMID: 34614993 DOI: 10.1364/oe.435841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
We evaluated the alignment-to-orientation conversion (AOC) at the cesium D1 line to improve a nonlinear magneto-optical rotation (NMOR) optical atomic magnetometer's signal amplitude and bandwidth. For the 6 2S1/2 F = 3 → 6 2P1/2 F' = 4 transition, the AOC-related NMOR achieves a 1.7-fold enhancement in signal amplitude compared to the conventional NMOR, benefiting from narrow linewidth and ultraweak power broadening. Therefore, an effective amplitude-to-linewidth ratio is maintained in the high-laser-power region. This method is beneficial for detecting high-frequency magnetic signals in nuclear magnetic resonance and biomagnetism, as the NMOR magnetometer bandwidth increases with laser power.
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13
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Fourcault W, Romain R, Le Gal G, Bertrand F, Josselin V, Le Prado M, Labyt E, Palacios-Laloy A. Helium-4 magnetometers for room-temperature biomedical imaging: toward collective operation and photon-noise limited sensitivity. OPTICS EXPRESS 2021; 29:14467-14475. [PMID: 33985169 DOI: 10.1364/oe.420031] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Optically-pumped magnetometers constitute a valuable tool for imaging biological magnetic signals without cryogenic cooling. Nowadays, numerous developments are being pursued using alkali-based magnetometers, which have demonstrated excellent sensitivities in the spin-exchange relaxation free (SERF) regime that requires heating to >100 °C. In contrast, metastable helium-4 based magnetometers work at any temperature, which allows a direct contact with the scalp, yielding larger signals and a better patient comfort. However former 4He magnetometers displayed large noises of >200 fT/Hz1/2 with 300-Hz bandwidth. We describe here an improved magnetometer reaching a sensitivity better than 50 fT/Hz1/2, nearly the photon shot noise limit, with a bandwidth of 2 kHz. Like other zero-field atomic magnetometers, these magnetometers can be operated in closed-loop architecture reaching several hundredths nT of dynamic range. A small array of 4 magnetometers operating in a closed loop has been tested with a successful correction of the cross-talks.
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14
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Hong HG, Park SE, Lee SB, Heo MS, Park J, Kim TH, Kim HY, Kwon TY. Chip-Scale Ultra-Low Field Atomic Magnetometer Based on Coherent Population Trapping. SENSORS 2021; 21:s21041517. [PMID: 33671625 PMCID: PMC7926612 DOI: 10.3390/s21041517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/16/2021] [Accepted: 02/19/2021] [Indexed: 11/30/2022]
Abstract
We report a chip-scale atomic magnetometer based on coherent population trapping, which can operate near zero magnetic field. By exploiting the asymmetric population among magnetic sublevels in the hyperfine ground state of cesium, we observe that the resonance signal acquires sensitivity to magnetic field in spite of degeneracy. A dispersive signal for magnetic field discrimination is obtained near-zero-field as well as for finite fields (tens of micro-tesla) in a chip-scale device of 0.94 cm3 volume. This shows that it can be readily used in low magnetic field environments, which have been inaccessible so far in miniaturized atomic magnetometers based on coherent population trapping. The measured noise floor of 300 pT/Hz1/2 at the zero-field condition is comparable to that of the conventional finite-field measurement obtained under the same conditions. This work suggests a way to implement integrated atomic magnetometers with a wide operating range.
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Affiliation(s)
- Hyun-Gue Hong
- Time and Frequency Group, Korea Research Institute of Standards and Science, Daejeon 34113, Korea; (S.E.P.); (S.-B.L.); (M.-S.H.); (T.Y.K.)
- Correspondence:
| | - Sang Eon Park
- Time and Frequency Group, Korea Research Institute of Standards and Science, Daejeon 34113, Korea; (S.E.P.); (S.-B.L.); (M.-S.H.); (T.Y.K.)
| | - Sang-Bum Lee
- Time and Frequency Group, Korea Research Institute of Standards and Science, Daejeon 34113, Korea; (S.E.P.); (S.-B.L.); (M.-S.H.); (T.Y.K.)
| | - Myoung-Sun Heo
- Time and Frequency Group, Korea Research Institute of Standards and Science, Daejeon 34113, Korea; (S.E.P.); (S.-B.L.); (M.-S.H.); (T.Y.K.)
| | - Jongcheol Park
- Department of Convergence Sensor, National NanoFab Center, Daejeon 34141, Korea; (J.P.); (T.H.K.); (H.Y.K.)
| | - Tae Hyun Kim
- Department of Convergence Sensor, National NanoFab Center, Daejeon 34141, Korea; (J.P.); (T.H.K.); (H.Y.K.)
| | - Hee Yeon Kim
- Department of Convergence Sensor, National NanoFab Center, Daejeon 34141, Korea; (J.P.); (T.H.K.); (H.Y.K.)
| | - Taeg Yong Kwon
- Time and Frequency Group, Korea Research Institute of Standards and Science, Daejeon 34113, Korea; (S.E.P.); (S.-B.L.); (M.-S.H.); (T.Y.K.)
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15
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Webb JL, Troise L, Hansen NW, Olsson C, Wojciechowski AM, Achard J, Brinza O, Staacke R, Kieschnick M, Meijer J, Thielscher A, Perrier JF, Berg-Sørensen K, Huck A, Andersen UL. Detection of biological signals from a live mammalian muscle using an early stage diamond quantum sensor. Sci Rep 2021; 11:2412. [PMID: 33510264 PMCID: PMC7844290 DOI: 10.1038/s41598-021-81828-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/28/2020] [Indexed: 12/12/2022] Open
Abstract
The 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/[Formula: see text] 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.
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Affiliation(s)
- James Luke Webb
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark.
| | - Luca Troise
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - Christoffer Olsson
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - Jocelyn Achard
- Laboratoire des Sciences des Procédés et des Matériaux, Université Sorbonne Paris Nord, 93430, Villetaneuse, France
| | - Ovidiu Brinza
- Laboratoire des Sciences des Procédés et des Matériaux, Université Sorbonne Paris Nord, 93430, Villetaneuse, France
| | - Robert Staacke
- Division Applied Quantum System, Felix Bloch Institute for Solid State Physics, Leipzig University, 04103, Leipzig, Germany
| | - Michael Kieschnick
- Division Applied Quantum System, Felix Bloch Institute for Solid State Physics, Leipzig University, 04103, Leipzig, Germany
| | - Jan Meijer
- Division Applied Quantum System, Felix Bloch Institute for Solid State Physics, Leipzig University, 04103, Leipzig, Germany
| | - Axel Thielscher
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, Denmark.,Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark
| | | | - Kirstine Berg-Sørensen
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Alexander Huck
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ulrik Lund Andersen
- Center for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Kgs. Lyngby, Denmark
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16
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Action potentials induce biomagnetic fields in carnivorous Venus flytrap plants. Sci Rep 2021; 11:1438. [PMID: 33446898 PMCID: PMC7809347 DOI: 10.1038/s41598-021-81114-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 12/30/2020] [Indexed: 12/17/2022] Open
Abstract
Upon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known that in the human brain, voltage changes in certain regions result from concerted electrical activity which, in the form of action potentials (APs), travels within nerve-cell arrays. Electro- and magnetophysiological techniques like electroencephalography, magnetoencephalography, and magnetic resonance imaging are used to record this activity and to diagnose disorders. Here we demonstrate that APs in a multicellular plant system produce measurable magnetic fields. Using atomic optically pumped magnetometers, biomagnetism associated with electrical activity in the carnivorous Venus flytrap, Dionaea muscipula, was recorded. Action potentials were induced by heat stimulation and detected both electrically and magnetically. Furthermore, the thermal properties of ion channels underlying the AP were studied. Beyond proof of principle, our findings pave the way to understanding the molecular basis of biomagnetism in living plants. In the future, magnetometry may be used to study long-distance electrical signaling in a variety of plant species, and to develop noninvasive diagnostics of plant stress and disease.
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17
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Silva M, Franco F, Leitao DC, Cardoso S, Freitas PP. Two-dimensional arrays of vertically packed spin-valves with picoTesla sensitivity at room temperature. Sci Rep 2021; 11:215. [PMID: 33420189 PMCID: PMC7794481 DOI: 10.1038/s41598-020-79856-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 12/08/2020] [Indexed: 11/09/2022] Open
Abstract
A new device architecture using giant magnetoresistive sensors demonstrates the capability to detect very low magnetic fields on the pT range. A combination of vertically packed spin-valve sensors with two-dimensional in-plane arrays, connected in series and in parallel, delivers a final detection level of 360 pT/[Formula: see text] at 10 Hz at room temperature. The device design is supported by an analytical model developed for a vertically packed spin-valve system, which takes into account all magnetic couplings present. Optimization concerning the spacer thickness and sensor physical dimensions depending on the number of pilled up spin-valves is necessary. To push the limits of detection, arrays of a large number of sensing elements (up to 440,000) are patterned with a geometry that improves sensitivity and in a configuration that reduces the resistance, leading to a lower noise level. The final device performance with pT detectivity is demonstrated in an un-shielded environment suitable for detection of bio-signals.
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Affiliation(s)
- Marilia Silva
- Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias (INESC-MN), 1000-029, Lisbon, Portugal. .,Instituto Superior Tecnico (IST), Universidade de Lisboa, 1040-001, Lisbon, Portugal.
| | - Fernando Franco
- Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias (INESC-MN), 1000-029, Lisbon, Portugal.,Instituto Superior Tecnico (IST), Universidade de Lisboa, 1040-001, Lisbon, Portugal.,Analog Devices, Limerick, V94 RT99, Ireland
| | - Diana C Leitao
- Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias (INESC-MN), 1000-029, Lisbon, Portugal.,Instituto Superior Tecnico (IST), Universidade de Lisboa, 1040-001, Lisbon, Portugal
| | - Susana Cardoso
- Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias (INESC-MN), 1000-029, Lisbon, Portugal.,Instituto Superior Tecnico (IST), Universidade de Lisboa, 1040-001, Lisbon, Portugal
| | - Paulo P Freitas
- Instituto de Engenharia de Sistemas e Computadores - Microsistemas e Nanotecnologias (INESC-MN), 1000-029, Lisbon, Portugal.,INL - International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
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18
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O'Dwyer C, Ingleby SJ, Chalmers IC, Griffin PF, Riis E. A feed-forward measurement scheme for periodic noise suppression in atomic magnetometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:045103. [PMID: 32357754 DOI: 10.1063/5.0002964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
We present an unshielded, double-resonance magnetometer in which we have implemented a feed-forward measurement scheme in order to suppress periodic magnetic noise arising from, and correlated with, the mains electricity alternating current line. The technique described here uses a single sensor to track ambient periodic noise and feed forward to suppress it in a subsequent measurement. This feed forward technique has shown significant noise suppression of electrical mains-noise features of up to 22 dB under the fundamental peak at 50 Hz, 3 dB at the first harmonic (100 Hz), and 21 dB at the second harmonic (150 Hz). This technique is software based, requires no additional hardware, and is easy to implement in an existing magnetometer.
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Affiliation(s)
- Carolyn O'Dwyer
- Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Stuart J Ingleby
- Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Iain C Chalmers
- Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Paul F Griffin
- Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Erling Riis
- Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
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19
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Murzin D, Mapps DJ, Levada K, Belyaev V, Omelyanchik A, Panina L, Rodionova V. Ultrasensitive Magnetic Field Sensors for Biomedical Applications. SENSORS (BASEL, SWITZERLAND) 2020; 20:E1569. [PMID: 32168981 PMCID: PMC7146409 DOI: 10.3390/s20061569] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/02/2020] [Accepted: 03/06/2020] [Indexed: 12/27/2022]
Abstract
The development of magnetic field sensors for biomedical applications primarily focuses on equivalent magnetic noise reduction or overall design improvement in order to make them smaller and cheaper while keeping the required values of a limit of detection. One of the cutting-edge topics today is the use of magnetic field sensors for applications such as magnetocardiography, magnetotomography, magnetomyography, magnetoneurography, or their application in point-of-care devices. This introductory review focuses on modern magnetic field sensors suitable for biomedicine applications from a physical point of view and provides an overview of recent studies in this field. Types of magnetic field sensors include direct current superconducting quantum interference devices, search coil, fluxgate, magnetoelectric, giant magneto-impedance, anisotropic/giant/tunneling magnetoresistance, optically pumped, cavity optomechanical, Hall effect, magnetoelastic, spin wave interferometry, and those based on the behavior of nitrogen-vacancy centers in the atomic lattice of diamond.
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Affiliation(s)
- Dmitry Murzin
- Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia; (K.L.); (V.B.); (A.O.); (L.P.); (V.R.)
| | - Desmond J. Mapps
- Faculty of Science and Engineering, University of Plymouth, Plymouth PL4 8AA, UK;
| | - Kateryna Levada
- Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia; (K.L.); (V.B.); (A.O.); (L.P.); (V.R.)
| | - Victor Belyaev
- Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia; (K.L.); (V.B.); (A.O.); (L.P.); (V.R.)
| | - Alexander Omelyanchik
- Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia; (K.L.); (V.B.); (A.O.); (L.P.); (V.R.)
| | - Larissa Panina
- Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia; (K.L.); (V.B.); (A.O.); (L.P.); (V.R.)
- National University of Science and Technology, MISiS, 119049 Moscow, Russia
| | - Valeria Rodionova
- Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia; (K.L.); (V.B.); (A.O.); (L.P.); (V.R.)
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20
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Core Concept: Quantum sensors probe uncharted territories, from Earth's crust to the human brain. Proc Natl Acad Sci U S A 2019; 116:16663-16665. [PMID: 31431560 DOI: 10.1073/pnas.1912326116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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