Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 9 de 9
Filter
Add more filters










Database
Language
Publication year range
1.
Nano Lett ; 18(3): 1882-1887, 2018 03 14.
Article in English | MEDLINE | ID: mdl-29470089

ABSTRACT

Efficient polarization of organic molecules is of extraordinary relevance when performing nuclear magnetic resonance (NMR) and imaging. Commercially available routes to dynamical nuclear polarization (DNP) work at extremely low temperatures, relying on the solidification of organic samples and thus bringing the molecules out of their ambient thermal conditions. In this work, we investigate polarization transfer from optically pumped nitrogen vacancy centers in diamond to external molecules at room temperature. This polarization transfer is described by both an extensive analytical analysis and numerical simulations based on spin bath bosonization and is supported by experimental data in excellent agreement. These results set the route to hyperpolarization of diffusive molecules in different scenarios and consequently, due to an increased signal, to high-resolution NMR.

2.
Phys Rev Lett ; 114(1): 017601, 2015 Jan 09.
Article in English | MEDLINE | ID: mdl-25615501

ABSTRACT

We report on the noise spectrum experienced by few nanometer deep nitrogen-vacancy centers in diamond as a function of depth, surface coating, magnetic field and temperature. Analysis reveals a double-Lorentzian noise spectrum consistent with a surface electronic spin bath in the low frequency regime, along with a faster noise source attributed to surface-modified phononic coupling. These results shed new light on the mechanisms responsible for surface noise affecting shallow spins at semiconductor interfaces, and suggests possible directions for further studies. We demonstrate dynamical decoupling from the surface noise, paving the way to applications ranging from nanoscale NMR to quantum networks.


Subject(s)
Diamond/chemistry , Models, Theoretical , Spectrum Analysis/methods , Electronics , Nanotechnology/methods , Nitrogen/chemistry , Signal-To-Noise Ratio
3.
Nat Commun ; 5: 4703, 2014 Aug 22.
Article in English | MEDLINE | ID: mdl-25146503

ABSTRACT

Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen-vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four (29)Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds.

4.
Nat Commun ; 5: 4739, 2014 Aug 27.
Article in English | MEDLINE | ID: mdl-25162729

ABSTRACT

Emitters of indistinguishable single photons are crucial for the growing field of quantum technologies. To realize scalability and increase the complexity of quantum optics technologies, multiple independent yet identical single-photon emitters are required. However, typical solid-state single-photon sources are inherently dissimilar, necessitating the use of electrical feedback or optical cavities to improve spectral overlap between distinct emitters. Here we demonstrate bright silicon vacancy (SiV(-)) centres in low-strain bulk diamond, which show spectral overlap of up to 91% and nearly transform-limited excitation linewidths. This is the first time that distinct single-photon emitters in the solid state have shown intrinsically identical spectral properties. Our results have impact on the application of single-photon sources for quantum optics and cryptography.

5.
Phys Rev Lett ; 111(6): 067601, 2013 Aug 09.
Article in English | MEDLINE | ID: mdl-23971612

ABSTRACT

We report the detection and polarization of nuclear spins in diamond at room temperature by using a single nitrogen-vacancy (NV) center. We use Hartmann-Hahn double resonance to coherently enhance the signal from a single nuclear spin while decoupling from the noisy spin bath, which otherwise limits the detection sensitivity. As a proof of principle, we (i) observe coherent oscillations between the NV center and a weakly coupled nuclear spin and (ii) demonstrate nuclear-bath cooling, which prolongs the coherence time of the NV sensor by more than a factor of 5. Our results provide a route to nanometer scale magnetic resonance imaging and novel quantum information processing protocols.


Subject(s)
Magnetic Resonance Spectroscopy , Models, Theoretical , Nuclear Physics/methods , Electrons , Nitrogen/chemistry
6.
Nano Lett ; 13(7): 3305-9, 2013 Jul 10.
Article in English | MEDLINE | ID: mdl-23738579

ABSTRACT

Nanometer-sized diamonds containing nitrogen-vacancy defect centers (NV) are promising nanosensors in biological environments due to their biocompatibility, bright fluorescence, and high magnetic sensitivity at ambient conditions. Here we report on the detection of ferritin molecules using magnetic noise induced by the inner paramagnetic iron as a contrast mechanism. We observe a significant reduction of both coherence and relaxation time due to the presence of ferritin on the surface of nanodiamonds. Our theoretical model is in excellent agreement with the experimental data and establishes this method as a novel sensing technology for proteins.


Subject(s)
Biosensing Techniques/instrumentation , Colorimetry/instrumentation , Metalloproteins/analysis , Nanoparticles/chemistry , Protein Array Analysis/instrumentation , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Metalloproteins/chemistry , Nanoparticles/ultrastructure , Particle Size
7.
Sci Rep ; 2: 401, 2012.
Article in English | MEDLINE | ID: mdl-22574249

ABSTRACT

A quantitative understanding of the dynamics of biological neural networks is fundamental to gaining insight into information processing in the brain. While techniques exist to measure spatial or temporal properties of these networks, it remains a significant challenge to resolve the neural dynamics with subcellular spatial resolution. In this work we consider a fundamentally new form of wide-field imaging for neuronal networks based on the nanoscale magnetic field sensing properties of optically active spins in a diamond substrate. We analyse the sensitivity of the system to the magnetic field generated by an axon transmembrane potential and confirm these predictions experimentally using electronically-generated neuron signals. By numerical simulation of the time dependent transmembrane potential of a morphologically reconstructed hippocampal CA1 pyramidal neuron, we show that the imaging system is capable of imaging planar neuron activity non-invasively at millisecond temporal resolution and micron spatial resolution over wide-fields.


Subject(s)
Brain Mapping/methods , Brain/physiology , Image Processing, Computer-Assisted/methods , Neurons/physiology , Algorithms , Animals , Biosensing Techniques/methods , CA1 Region, Hippocampal/physiology , Humans , Magnetic Fields , Models, Neurological , Nanotechnology/methods , Nerve Net/physiology
8.
Nat Nanotechnol ; 6(6): 358-63, 2011 May 08.
Article in English | MEDLINE | ID: mdl-21552253

ABSTRACT

Fluorescent particles are routinely used to probe biological processes. The quantum properties of single spins within fluorescent particles have been explored in the field of nanoscale magnetometry, but not yet in biological environments. Here, we demonstrate optically detected magnetic resonance of individual fluorescent nanodiamond nitrogen-vacancy centres inside living human HeLa cells, and measure their location, orientation, spin levels and spin coherence times with nanoscale precision. Quantum coherence was measured through Rabi and spin-echo sequences over long (>10 h) periods, and orientation was tracked with effective 1° angular precision over acquisition times of 89 ms. The quantum spin levels served as fingerprints, allowing individual centres with identical fluorescence to be identified and tracked simultaneously. Furthermore, monitoring decoherence rates in response to changes in the local environment may provide new information about intracellular processes. The experiments reported here demonstrate the viability of controlled single spin probes for nanomagnetometry in biological systems, opening up a host of new possibilities for quantum-based imaging in the life sciences.


Subject(s)
HeLa Cells/metabolism , Magnetics/methods , Molecular Probe Techniques/instrumentation , Nanodiamonds/chemistry , Nitrogen/chemistry , Quantum Dots , Quantum Theory , Cell Line , Cytoplasm/metabolism , Diamond/chemistry , Fluorescence , Humans , Magnetic Resonance Spectroscopy , Nanotechnology/methods , Particle Size
9.
Proc Natl Acad Sci U S A ; 106(32): 13457-62, 2009 Aug 11.
Article in English | MEDLINE | ID: mdl-19633185

ABSTRACT

In contrast to most stimulated lymphocytes, B cells exposed to Toll-like receptor 9 ligands are nonself-adherent, allowing individual cells and families to be followed in vitro for up to 5 days. These B cells undergo phases typical of an adaptive response, dividing up to 6 times before losing the impetus for further growth and division and eventually dying by apoptosis. Using long-term microscopic imaging, accurate histories of individual lymphocyte fates were collected. Quantitative analysis of family relationships revealed that times to divide of siblings were strongly related but these correlations were progressively lost through consecutive divisions. A weaker, but significant, correlation was also found for death times among siblings. Division cessation is characterized by a loss of cell growth and the division in which this occurs is strongly inherited from the original founder cell and is related to the size this cell reaches before its first division. Thus, simple division-based dilution of factors synthesized during the first division may control the maximum division reached by stimulated cells. The stochastic distributions of times to divide, times to die, and divisions reached are also measured. Together, these results highlight the internal cellular mechanisms that control immune responses and provide a foundation for the development of new mathematical models that are correct at both single-cell and population levels.


Subject(s)
B-Lymphocytes/cytology , Cell Lineage , Animals , B-Lymphocytes/drug effects , B-Lymphocytes/immunology , Cell Cycle/drug effects , Cell Death/drug effects , Cell Lineage/drug effects , Cell Proliferation/drug effects , Cell Size/drug effects , Cellular Senescence/drug effects , Lymphocyte Activation/drug effects , Mice , Mice, Inbred C57BL , Oligodeoxyribonucleotides/pharmacology , Stochastic Processes , Time Factors
SELECTION OF CITATIONS
SEARCH DETAIL
...