@article {1627, title = {Zero-field nuclear magnetic resonance spectroscopy of viscous liquids}, journal = {Journal of Magnetic Resonance}, volume = {250}, year = {2015}, month = {01/2015}, pages = {1-6}, doi = {Doi:10.1016/j.jmr.2014.10.012}, author = {Shimizu, Y. and Blanchard, J.W. and Pustelny, S. and Saielli, G. and Bagno, A. and Ledbetter, M.P. and Budker, D. and Pines, A.} } @article {1450, title = {Long-lived Heteronuclear Spin-Singlet States in Liquids at a Zero Magnetic Field}, journal = {Physical Review Letters}, volume = {112}, year = {2014}, pages = {077601}, chapter = {077601}, author = {Emondts, M. and Ledbetter, M. P. and Pustelny, S. and Theis, T. and Patton, B. and Blanchard, J. W. and Butler, M. C. and Budker, D. and Pines, A.} } @article {1475, title = {Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer (Cover Article)}, journal = {Angewandte Chemie}, volume = {53}, year = {2014}, month = {09/2014}, pages = {1-6}, doi = {DOI: 10.1002/anie.201403416}, author = {Ganssle, P. J. and Shin, H. D. and Seltzer, S. J. and Bajaj, V.S. and Ledbetter, M. P. and Budker, D. and Knappe, S. and Kitching, J. and Pines, A} } @article {245, title = {Fundamental Aspects of Parahydrogen Enhanced Low-Field Nuclear Magnetic Resonance}, journal = {Physical Review Letters}, volume = {110}, year = {2013}, note = {Phys Rev Lett113RITimes Cited:0Cited References Count:28}, month = {Mar 26}, pages = {137602}, abstract = {

We report new phenomena in low-field H-1 nuclear magnetic resonance (NMR) spectroscopy using parahydrogen induced polarization (PHIP), enabling determination of chemical shift differences, delta nu, and the scalar coupling constant J. NMR experiments performed with thermal polarization in millitesla magnetic fields do not allow the determination of scalar coupling constants for homonuclear coupled spins in the inverse weak coupling regime (delta nu \< J). We show here that low-field PHIP experiments in the inverse weak coupling regime enable the precise determination of delta nu and J. Furthermore we experimentally prove that observed splittings are related to delta nu in a nonlinear way. Naturally abundant C-13 and Si-29 isotopes lead to heteronuclear J-coupled H-1-multiplet lines with amplitudes significantly enhanced compared to the amplitudes for thermally prepolarized spins. PHIP-enhanced NMR in the millitesla regime allows us to measure characteristic NMR parameters in a single scan using samples containing rare spins in natural abundance. DOI: 10.1103/PhysRevLett.110.137602

}, keywords = {exchange}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.110.137602}, url = {://WOS:000316685100032}, author = {Colell, J. and Turschmann, P. and Gloggler, S. and Schleker, P. and Theis, T. and Ledbetter, M. and Budker, D. and Pines, A. and Blumich, B. and Appelt, S.} } @article {247, title = {High-Resolution Zero-Field NMR J-Spectroscopy of Aromatic Compounds}, journal = {Journal of the American Chemical Society}, volume = {135}, year = {2013}, note = {J Am Chem Soc103RNTimes Cited:0Cited References Count:59}, month = {02/2013}, pages = {3607-3612}, abstract = {

We report the acquisition and interpretation of nuclear magnetic resonance (NMR) J-spectra at zero magnetic field for a series of benzene derivatives, demonstrating the analytical capabilities of zero-field NMR The zeroth-order spectral patterns do not overlap, which allows for straightforward determination of the spin interactions of substituent functional groups. Higher-order effects cause additional line splittings, revealing additional molecular information. We demonstrate resonance linewidths as narrow as 11 mHz, permitting resolution of minute frequency differences and precise determination of long-range J-couplings. The measurement of J-couplings with the high precision offered by zero-field NMR may allow further refinements in the determination of molecular structure and conformation.

}, keywords = {density}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja312239v}, url = {://WOS:000315936700050}, author = {Blanchard, J. W. and Ledbetter, M. P. and Theis, T. and Butler, M. C. and Budker, D. and Pines, A.} } @article {1074, title = {Sensitive magnetic control of ensemble nuclear spin hyperpolarization in diamond}, journal = {Nature Communications}, volume = {4}, year = {2013}, note = {Nature communicationsWang, Hai-JingShin, Chang SAvalos, Claudia ESeltzer, Scott JBudker, DmitryPines, AlexanderBajaj, Vikram SengEngland2013/06/06 06:00Nat Commun. 2013 Jun 5;4:1940. doi: 10.1038/ncomms2930.}, month = {June 5, 2013}, pages = {1940}, chapter = {1940}, abstract = {

Dynamic nuclear polarization, which transfers the spin polarization of electrons to nuclei, is routinely applied to enhance the sensitivity of nuclear magnetic resonance. This method is particularly useful when spin hyperpolarization can be produced and controlled optically or electrically. Here we show complete polarization of nuclei located near optically polarized nitrogen-vacancy centres in diamond. Close to the ground-state level anti-crossing condition of the nitrogen-vacancy electron spins, (13)C nuclei in the first shell are polarized in a pattern that depends sensitively upon the magnetic field. Based on the anisotropy of the hyperfine coupling and of the optical polarization mechanism, we predict and observe a reversal of the nuclear spin polarization with only a few millitesla change in the magnetic field. This method of magnetic control of high nuclear polarization at room temperature can be applied in sensitivity enhanced nuclear magnetic resonance of bulk nuclei, nuclear-based spintronics, and quantum computation in diamond.

}, isbn = {2041-1723 (Linking)}, doi = {10.1038/ncomms2930}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23736952}, author = {Wang, H. J. and Shin, C. S. and Avalos, C. E. and Seltzer, S. J. and Budker, D. and Pines, A. and Bajaj, V. S.} } @article {251, title = {Liquid-State Nuclear Spin Comagnetometers}, journal = {Physical Review Letters}, volume = {108}, year = {2012}, note = {Phys Rev Lett973FATimes Cited:0Cited References Count:36}, month = {Jun 15}, abstract = {

We discuss nuclear spin comagnetometers based on ultralow-field nuclear magnetic resonance in mixtures of miscible solvents, each rich in a different nuclear spin. In one version thereof, Larmor precession of protons and F-19 nuclei in a mixture of thermally polarized pentane and hexafluorobenzene is monitored via a sensitive alkali-vapor magnetometer. We realize transverse relaxation times in excess of 20 s and suppression of magnetic field fluctuations by a factor of 3400. We estimate it should be possible to achieve single-shot sensitivity of about 5 x 10(-9) Hz, or about 5 x 10(-11) Hz in approximate to 1 day of integration. In a second version, spin precession of protons and Xe-129 nuclei in a mixture of pentane and hyperpolarized liquid xenon is monitored using superconducting quantum interference devices. Application to spin-gravity experiments, electric dipole moment experiments, and sensitive gyroscopes is discussed.

}, keywords = {nmr}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.108.243001}, url = {://WOS:000306342000010}, author = {Ledbetter, M. P. and Pustelny, S. and Budker, D. and Romalis, M. V. and Blanchard, J. W. and Pines, A.} } @article {249, title = {Room-temperature operation of a radiofrequency diamond magnetometer near the shot-noise limit}, journal = {Journal of Applied Physics}, volume = {112}, year = {2012}, note = {J Appl Phys061ECTimes Cited:1Cited References Count:15}, month = {Dec 15, 2012}, pages = {124519}, chapter = {124519}, abstract = {

We operate a nitrogen-vacancy (NV-) diamond magnetometer at ambient temperatures and study the dependence of its bandwidth on experimental parameters including optical and microwave excitation powers. A model based on the Bloch equations is used to analyze the NV center\&$\#$39;s response time, tau, during continuous optical and microwave irradiation, and tau(-1) is shown to be a weighted average of T-1(-1) and T-2(-1), where T-1 and T-2 are the longitudinal and transverse relaxation times of the electron spin during optical irradiation. We measured a maximum detection bandwidth of similar to 1.6 MHz with optical excitation intensity of similar to 2.3MW/cm(2), limited by the available optical power. The sensitivity of the NV ensemble for continuous-wave magnetometry in the presence of photon shot noise is analyzed. Two detection schemes are compared, one involving modulation of the fluorescence by an oscillating magnetic field while the microwave frequency is held constant, and the other involving double modulation of the fluorescence when the microwave frequency is modulated during the detection. For the first of these methods, we measure a sensitivity of 4.6 +/- 0.3 nT/root Hz, unprecedented in a detector with this active volume of similar to 10 mu m(3) and close to the photon-shot-noise limit of our experiment. The measured bandwidth and sensitivity of our device should allow detection of micro-scale NMR signals with microfluidic devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4771924]

}, keywords = {spin}, isbn = {0021-8979}, doi = {Doi 10.1063/1.4771924}, url = {http://link.aip.org/link/doi/10.1063/1.4771924}, author = {Shin, C. S. and Avalos, C. E. and Butler, M. C. and Trease, D. R. and Seltzer, S. J. and Mustonen, J. P. and Kennedy, D. J. and Acosta, V. M. and Budker, D. and Pines, A. and Bajaj, V. S.} } @article {248, title = {Zero-Field NMR Enhanced by Parahydrogen in Reversible Exchange}, journal = {Journal of the American Chemical Society}, volume = {134}, year = {2012}, note = {J Am Chem Soc909GLTimes Cited:2Cited References Count:40}, month = {02/2012}, pages = {3987-3990}, abstract = {

We have recently demonstrated that sensitive and chemically specific NMR spectra can be recorded in the absence of a magnetic field using hydrogenative parahydrogen induced polarization (PHIP)(1-3) and detection with an optical atomic magnetometer. Here, we show that non-hydrogenative para-hydrogen-induced polarization(4-6) (NH-PHIP) can also dramatically enhance the sensitivity of zero-field NMR. We demonstrate the detection of pyridine, at concentrations as low as 6 mM in a sample volume of 250 mu L, with sufficient sensitivity to resolve all identifying spectral features, as supported by numerical simulations. Because the NH-PHIP mechanism is nonreactive, operates in situ, and eliminates the need for a prepolarizing magnet, its combination with optical atomic magnetometry will greatly broaden the analytical capabilities of zero-field and low-field NMR.

}, keywords = {gas}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja2112405}, url = {://WOS:000301550800015}, author = {Theis, T. and Ledbetter, M. P. and Kervern, G. and Blanchard, J. W. and Ganssle, P. J. and Butler, M. C. and Shin, H. D. and Budker, D. and Pines, A.} } @article {258, title = {Near-Zero-Field Nuclear Magnetic Resonance}, journal = {Physical Review Letters}, volume = {107}, year = {2011}, note = {Phys Rev Lett813YOTimes Cited:5Cited References Count:26}, month = {Sep 1}, abstract = {

We investigate nuclear magnetic resonance (NMR) in near zero field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J coupling). This is in stark contrast to the high-field case, where heteronuclear J couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with nontrivial spectra.

}, keywords = {mri}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.107.107601}, url = {://WOS:000294406600017}, author = {Ledbetter, M. P. and Theis, T. and Blanchard, J. W. and Ring, H. and Ganssle, P. and Appelt, S. and Blumich, B. and Pines, A. and Budker, D.} } @article {253, title = {Parahydrogen-enhanced zero-field nuclear magnetic resonance}, journal = {Nature Physics}, volume = {7}, year = {2011}, note = {Nat Phys786FYTimes Cited:9Cited References Count:31}, month = {Jul}, pages = {571-575}, abstract = {

Nuclear magnetic resonance, conventionally detected in magnetic fields of several tesla, is a powerful analytical tool for the determination of molecular identity, structure and function. With the advent of prepolarization methods and detection schemes using atomic magnetometers or superconducting quantum interference devices, interest in NMR in fields comparable to the Earth\&$\#$39;s magnetic field and below (down to zero field) has been revived. Despite the use of superconducting quantum interference devices or atomic magnetometers, low-field NMR typically suffers from low sensitivity compared with conventional high-field NMR. Here we demonstrate direct detection of zero-field NMR signals generated through parahydrogen-induced polarization, enabling high-resolution NMR without the use of any magnets. The sensitivity is sufficient to observe spectra exhibiting (13)C-(1)H scalar nuclear spin-spin couplings (known as J couplings) in compounds with (13)C in natural abundance, without the need for signal averaging. The resulting spectra show distinct features that aid chemical fingerprinting.

}, keywords = {order}, isbn = {1745-2473}, doi = {Doi 10.1038/Nphys1986}, url = {://WOS:000292290000017}, author = {Theis, T. and Ganssle, P. and Kervern, G. and Knappe, S. and Kitching, J. and Ledbetter, M. P. and Budker, D. and Pines, A.} } @article {256, title = {Relaxivity of Gadolinium Complexes Detected by Atomic Magnetometry}, journal = {Magnetic Resonance in Medicine}, volume = {66}, year = {2011}, note = {Magn Reson Med799AVTimes Cited:1Cited References Count:23}, month = {Aug}, pages = {605-608}, abstract = {

Laser atomic magnetomeby is a portable and low-cost yet highly sensitive method for low magnetic field detection. In this work, the atomic magnetometer was used in a remote-detection geometry to measure the relaxivity of aqueous gadolinium-diethylenetriamine pentaacetic acid Gd(DTPA) at the Earth\&$\#$39;s magnetic field (40 mu T). The measured relaxivity of 9.7 +/- 2.0 s(-1) mM(-1) is consistent with field-cycling experiments measured at slightly higher magnetic fields, but no cryogens or strong and homogeneous magnetic field were required for this experiment. The field-independent sensitivity of 80 fT Hz(-1/2) allowed an in vitro detection limit of similar to 10 mu M Gd(DTPA) to be measured in aqueous buffer solution. The low detection limit and enhanced relaxivity of Gd-containing complexes at Earth\&$\#$39;s field motivate continued development of atomic magnetometry toward medical applications. Magn Reson Med 66:605-608, 2011. (C) 2011 Wiley-Liss, Inc.

}, keywords = {nmr}, isbn = {0740-3194}, doi = {Doi 10.1002/Mrm.22811}, url = {://WOS:000293256800033}, author = {Michalak, D. J. and Xu, S. J. and Lowery, T. J. and Crawford, C. W. and Ledbetter, M. and Bouchard, L. S. and Wemmer, D. E. and Budker, D. and Pines, A.} } @article {260, title = {Investigation of antirelaxation coatings for alkali-metal vapor cells using surface science techniques}, journal = {Journal of Chemical Physics}, volume = {133}, year = {2010}, note = {J. Chem. Phys.ISI Document Delivery No.: 667NNTimes Cited: 6Cited Reference Count: 81Seltzer, S. J. Michalak, D. J. Donaldson, M. H. Balabas, M. V. Barber, S. K. Bernasek, S. L. Bouchiat, M. -A. Hexemer, A. Hibberd, A. M. Kimball, D. F. Jackson Jaye, C. Karaulanov, T. Narducci, F. A. Rangwala, S. A. Robinson, H. G. Shmakov, A. K. Voronov, D. L. Yashchuk, V. V. Pines, A. Budker, D.Office of Science, Office of Basic Energy Sciences, Materials Sciences Division and Nuclear Science Division, of the U. S. Department of Energy [DE-AC02-05CH11231]; NSF/DST [PHY-0425916]; Office of Naval Research (ONR) [N0001409WX21049]The authors thank Daniel Fischer, Kristin Schmidt, and Ed Kramer for assistance with the NEXAFS measurements, and Joel Ager, Joshua Wnuk, David Trease, and Gwendal Kervern for helpful discussions and other assistance. S.J.S., D.J.M., M. H. D., A. P., and D. B., the Advanced Light Source, and the DSC, FTIR, and AFM studies were supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences Division and Nuclear Science Division, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory. Other parts of this work were funded by the NSF/DST under Grant No. PHY-0425916 for U.S.-India cooperative research, by an Office of Naval Research (ONR) MURI grant, and by ONR under Grant No. N0001409WX21049.AMER INST PHYSICSMELVILLE}, month = {October 11, 2010}, pages = {144703}, type = {Article}, chapter = {144703}, abstract = {

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10 000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of CvC double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials. (C) 2010 American Institute of Physics. [doi:10.1063/1.3489922]

}, keywords = {SPECTROSCOPY}, isbn = {0021-9606}, doi = {10.1063/1.3489922}, url = {http://link.aip.org/link/doi/10.1063/1.3489922}, author = {Seltzer, S. J. and Michalak, D. J. and Donaldson, M. H. and Balabas, M. V. and Barber, S. K. and Bernasek, S. L. and Bouchiat, M. A. and Hexemer, A. and Hibberd, A. M. and Kimball, D. F. J. and Jaye, C. and Karaulanov, T. and Narducci, F. A. and Rangwala, S. A. and Robinson, H. G. and Shmakov, A. K. and Voronov, D. L. and Yashchuk, V. V. and Pines, A. and Budker, D.} } @article {268, title = {Optical detection of NMR J-spectra at zero magnetic field}, journal = {Journal of Magnetic Resonance}, volume = {199}, year = {2009}, note = {J Magn Reson456YJTimes Cited:19Cited References Count:26}, month = {Jul}, pages = {25-29}, abstract = {

Scalar couplings of the form JI(1) . I(2) between nuclei impart valuable information about molecular structure to nuclear magnetic-resonance spectra. Here we demonstrate direct detection of J-spectra due to both heteronuclear and homonuclear J-coupling in a zero-field environment where the Zeeman interaction is completely absent. We show that characteristic functional groups exhibit distinct spectra with straightforward interpretation for chemical identification. Detection is performed with a microfabricated optical atomic magnetometer, providing high sensitivity to samples of microliter volumes. We obtain 0.1 Hz linewidths and measure scalar-coupling parameters with 4-mHz statistical uncertainty. We anticipate that the technique described here will provide a new modality for high-precision\" J spectroscopy\" using small samples oil microchip devices for multiplexed Screening, assaying, and sample identification in chemistry and biomedicine. (C) 2009 Elsevier Inc. All rights reserved.

}, keywords = {cells}, isbn = {1090-7807}, doi = {Doi 10.1016/J.Jmr.2009.03.008}, url = {://WOS:000266890300004}, author = {Ledbetter, M. P. and Crawford, C. W. and Pines, A. and Wemmer, D. E. and Knappe, S. and Kitching, J. and Budker, D.} } @article {273, title = {Flow in Porous Metallic Materials: A Magnetic Resonance Imaging Study}, journal = {Journal of Magnetic Resonance Imaging}, volume = {28}, year = {2008}, note = {J Magn Reson Imaging367QCTimes Cited:5Cited References Count:22}, month = {Nov}, pages = {1299-1302}, abstract = {

Purpose: To visualize flow dynamics of analytes inside porous metallic materials with laser-detected magnetic resonance imaging (MRI).Materials and Methods: We examine the flow of nuclear-polarized water in a porous stainless steel cylinder. Laser-detected MRI utilizes a sensitive optical atomic magnetometer as the detector. Imaging was performed in a remote-detection mode: the encoding was conducted in the Earth\&$\#$39;s magnetic field, and detection is conducted downstream of the encoding location. Conventional MRI (7T) was also performed for comparison.Results: Laser-detected MRI clearly showed MR images of water flowing through the sample, whereas conventional MRI provided no image.Conclusion: We demonstrated the viability of laser-detected MRI at low-field for studying porous metallic materials, extending MRI techniques to a new group of systems that is normally not accessible to conventional MRI.

}, keywords = {mri}, isbn = {1053-1807}, doi = {Doi 10.1002/Jmri.21532}, url = {://WOS:000260566100033}, author = {Xu, S. J. and Harel, E. and Michalak, D. J. and Crawford, C. W. and Budker, D. and Pines, A.} } @article {281, title = {Fluid-flow characterization with nuclear spins without magnetic resonance}, journal = {Applied Physics Letters}, volume = {93}, year = {2008}, note = {Appl Phys Lett345DHTimes Cited:2Cited References Count:20}, month = {Sep 1}, abstract = {

A technique for noninvasive monitoring of flow inside metallic enclosures using laser-based atomic magnetometry is introduced. The analyte is labeled via nuclear magnetization by magnets, thereby combining the polarization and encoding steps. No radiofrequency or audiofrequency pulses are involved. We demonstrate detection of flow inside an aluminum pipe with an inner diameter of 4.9 mm that has a constriction with a diameter of 1.6 mm and a length of 6.4 mm. The results agree with a model of spin density and relaxation indicating that our technique allows for fast, quantitative, and noninvasive diagnostics of flow with potential applications discussed below. (c) 2008 American Institute of Physics.

}, keywords = {mri}, isbn = {0003-6951}, doi = {Doi 10.1063/1.2977773}, url = {://WOS:000258975800042}, author = {Crawford, C. W. and Xu, S. J. and Siegel, E. J. and Budker, D. and Pines, A.} } @article {275, title = {Remote detection of nuclear magnetic resonance with an anisotropic magnetoresistive sensor}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {105}, year = {2008}, note = {P Natl Acad Sci USA266XBTimes Cited:8Cited References Count:17}, month = {Feb 19}, pages = {2271-2273}, abstract = {

We report the detection of nuclear magnetic resonance (NMR) using an anisotropic magnetoresistive (AMR) sensor. A \"remote-detection\" arrangement was used in which protons in flowing water were prepolarized in the field of a superconducting NMR magnet, adiabatically inverted, and subsequently detected with an AMR sensor situated downstream from the magnet and the adiabatic inverter. AMR sensing is well suited for NMR detection in microfluidic \"lab-on-a-chip\" applications because the sensors are small, typically on the order of 10 mu m. An estimate of the sensitivity for an optimized system indicates that approximate to 6 x 10(13) protons in a volume of 1,000 mu m(3), prepolarized in a 10-kG magnetic field, can be detected with a signal-to-noise ratio of 3 in a 1-Hz bandwidth. This level of sensitivity is competitive with that demonstrated by microcoils in superconducting magnets and with the projected sensitivity of microfabricated atomic magnetometers.

}, keywords = {mri}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0712129105}, url = {://WOS:000253469900006}, author = {Verpillat, F. and Ledbetter, M. P. and Xu, S. and Michalak, D. J. and Hilty, C. and Bouchard, L. S. and Antonijevic, S. and Budker, D. and Pines, A.} } @article {274, title = {Submillimeter-resolution magnetic resonance imaging at the Earth{\textquoteright}s magnetic field with an atomic magnetometer}, journal = {Physical Review A}, volume = {78}, year = {2008}, note = {Phys Rev A333VGTimes Cited:18Cited References Count:24}, month = {Jul}, abstract = {

Magnetic resonance imaging in the Earth\&$\#$39;s magnetic field is achieved using a sensitive atomic magnetometer for detection. We demonstrate images with a submillimeter resolution by recording the flow of two water paths meeting at a T-shaped mixer. The high homogeneity of the Earth\&$\#$39;s field allows the use of weak gradient fields which circumvent the concomitant-field effect. To distinguish the two input channels, we employed selective polarization, which is a unique and noninvasive labeling method for low-field magnetic resonance imaging. Our technique imposes minimal physical constraints on the object under study, in contrast to conventional high-field magnetic resonance imaging. This technique is applicable for microfluidic imaging in laboratory-on-a-chip devices.

}, keywords = {nmr}, isbn = {1050-2947}, doi = {Doi 10.1103/Physreva.78.013404}, url = {://WOS:000258180300141}, author = {Xu, S. and Crawford, C. W. and Rochester, S. and Yashchuk, V. and Budker, D. and Pines, A.} } @article {279, title = {Zero-field remote detection of NMR with a microfabricated atomic magnetometer}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {105}, year = {2008}, note = {P Natl Acad Sci USA266XBTimes Cited:37Cited References Count:26}, month = {Feb 19}, pages = {2286-2290}, abstract = {

We demonstrate remote detection of nuclear magnetic resonance (NMR) with a microchip sensor consisting of a microfluidic channel and a microfabricated vapor cell (the heart of an atomic magnetometer). Detection occurs at zero magnetic field, which allows operation of the magnetometer in the spin-exchange relaxation-free (SERF) regime and increases the proximity of sensor and sample by eliminating the need for a solenoid to create a leading field. We achieve pulsed NMR linewidths of 26 Hz, limited, we believe, by the residence time and flow dispersion in the encoding region. In a fully optimized system, we estimate that for 1 s of integration, 7 x 10(13) protons in a volume of 1 mm(3), prepolarized in a 10-kG field, can be detected with a signal-to-noise ratio of approximate to 3. This level of sensitivity is competitive with that demonstrated by microcoils in 100-kG magnetic fields, without requiring superconducting magnets.

}, keywords = {mri}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0711505105}, url = {://WOS:000253469900009}, author = {Ledbetter, M. P. and Savukov, I. M. and Budker, D. and Shah, V. and Knappe, S. and Kitching, J. and Michalak, D. J. and Xu, S. and Pines, A.} } @article {293, title = {Application of atomic magnetometry in magnetic particle detection}, journal = {Applied Physics Letters}, volume = {89}, year = {2006}, note = {Appl Phys Lett112PJTimes Cited:9Cited References Count:18}, month = {Nov 27}, abstract = {

The authors demonstrate the detection of magnetic particles carried by water in a continuous flow using an atomic magnetic gradiometer. Studies on three types of magnetic particles are presented: a single cobalt particle (diameter similar to 150 mu m, multidomain), a suspension of superparamagnetic magnetite particles (diameter similar to 1 mu m), and ferromagnetic cobalt nanoparticles (diameter similar to 10 nm). Estimated detection limits are 20 mu m diameter for a single cobalt particle at a water flow rate of 30 ml/min, 5x10(3) magnetite particles at 160 ml/min, and 50 pl for the ferromagnetic fluid of cobalt nanoparticles at 130 ml/min. Possible applications of their method are discussed.

}, keywords = {system}, isbn = {0003-6951}, doi = {Doi 10.1063/1.2400077}, url = {://WOS:000242538500151}, author = {Xu, S. and Donaldson, M. H. and Pines, A. and Rochester, S. M. and Budker, D. and Yashchuk, V. V.} } @article {292, title = {Magnetic resonance imaging with an optical atomic magnetometer}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {103}, year = {2006}, note = {P Natl Acad Sci USA077NITimes Cited:58Cited References Count:18}, month = {Aug 22}, pages = {12668-12671}, abstract = {

We report an approach for the detection of magnetic resonance imaging without superconducting magnets and cryogenics: optical atomic magnetometry. This technique possesses a high sensitivity independent of the strength of the static magnetic field, extending the applicability of magnetic resonance imaging to low magnetic fields and eliminating imaging artifacts associated with high fields. By coupling with a remote-detection scheme, thereby improving the filling factor of the sample, we obtained time-resolved flow images of water with a temporal resolution of 0.1 s and spatial resolutions of 1.6 mm perpendicular to the flow and 4.5 mm along the flow. Potentially inexpensive, compact, and mobile, our technique provides a viable alternative for MRI detection with substantially enhanced sensitivity and time resolution for various situations where traditional MRI is not optimal.

}, keywords = {gas}, isbn = {0027-8424}, doi = {Doi 10.1073/Pnas.0605396103}, url = {://WOS:000240035900006}, author = {Xu, S. J. and Yashchuk, V. V. and Donaldson, M. H. and Rochester, S. M. and Budker, D. and Pines, A.} } @article {321, title = {Hyperpolarized xenon nuclear spins detected by optical atomic magnetometry}, journal = {Physical Review Letters}, volume = {93}, year = {2004}, note = {Phys Rev Lett863ATTimes Cited:32Cited References Count:22}, month = {Oct 15}, abstract = {

We report the use of an atomic magnetometer based on nonlinear magneto-optical rotation with frequency-modulated light to detect nuclear magnetization of xenon gas. The magnetization of a spin-exchange-polarized xenon sample (1.7 cm(3) at a pressure of 5 bars, natural isotopic abundance, polarization 1\%), prepared remotely to the detection apparatus, is measured with an atomic sensor. An average magnetic field of similar to10 nG induced by the xenon sample on the 10 cm diameter atomic sensor is detected with signal-to-noise ratio similar to10, limited by residual noise in the magnetic environment. The possibility of using modern atomic magnetometers as detectors of nuclear magnetic resonance and in magnetic resonance imaging is discussed. Atomic magnetometers appear to be ideally suited for emerging low-field and remote-detection magnetic resonance applications.

}, keywords = {mri}, isbn = {0031-9007}, doi = {Doi 10.1103/Physrevlett.93.160801}, url = {://WOS:000224533300012}, author = {Yashchuk, V. V. and Granwehr, J. and Kimball, D. F. and Rochester, S. M. and Trabesinger, A. H. and Urban, J. T. and Budker, D. and Pines, A.} }