10 research outputs found
Diamond Surface Functionalization via Visible Light-Driven C-H Activation for Nanoscale Quantum Sensing
Nitrogen-vacancy centers in diamond are a promising platform for nanoscale
nuclear magnetic resonance sensing. Despite significant progress towards using
NV centers to detect and localize nuclear spins down to the single spin level,
NV-based spectroscopy of individual, intact, arbitrary target molecules remains
elusive. NV molecular sensing requires that target molecules are immobilized
within a few nanometers of NV centers with long spin coherence time. The inert
nature of diamond typically requires harsh functionalization techniques such as
thermal annealing or plasma processing, limiting the scope of functional groups
that can be attached to the surface. Solution-phase chemical methods can be
more readily generalized to install diverse functional groups, but they have
not been widely explored for single-crystal diamond surfaces. Moreover,
realizing shallow NV centers with long spin coherence times requires highly
ordered single-crystal surfaces, and solution-phase functionalization has not
yet been shown to be compatible with such demanding conditions. In this work,
we report a versatile strategy to directly functionalize C-H bonds on
single-crystal diamond surfaces under ambient conditions using visible light.
This functionalization method is compatible with charge stable NV centers
within 10 nm of the surface with spin coherence times comparable to the state
of the art. As a proof of principle, we use shallow ensembles of NV centers to
detect nuclear spins from functional groups attached to the surface. Our
approach to surface functionalization based on visible light-driven C-H bond
activation opens the door to deploying NV centers as a broad tool for chemical
sensing and single-molecule spectroscopy
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Hyperfine-enhanced gyromagnetic ratio of a nuclear spin in diamond
The nuclear spin gyromagnetic ratio can be enhanced by hyperfine coupling to the electronic spin. Here we show wide tunability of this enhancement on a (15)Nnuclear spin intrinsic to a single nitrogen-vacancy center in diamond. We perform control of the nuclear spin near the ground state level anti-crossing (GSLAC), where the enhancement of the gyromagnetic ratio from the ground state hyperfine coupling is maximized. We demonstrate a two order of magnitude enhancement of the effective nuclear gyromagnetic ratio compared to the value obtained at 500 G, a typical operating field that is suitable for nuclear spin polarization. Finally, we show that with strong enhancements, the nuclear spin ultimately suffers dephasing from the inhomogeneous broadening of the NMRtransition frequency at the GSLAC
Serum ibuprofen levels of extremely preterm infants treated prophylactically with oral ibuprofen to prevent patent ductus arteriosus
<p>The aim of this study was to explore the effects of early oral ibuprofen administration on the incidence of hemodynamically significant patent ductus arteriosus (hsPDA) and define the association between serum ibuprofen levels and ductal closure.</p><p>Preterm infants with a gestational age of <28 weeks and/or birth weight of <1,000 g were randomized either to the intervention (ibuprofen prophylaxis) or control group. The intervention group received oral ibuprofen 10 mg/kg within 12-24 h after birth followed by 5 mg/kg at 24 and 48 h. Serum ibuprofen levels after the treatment were analyzed in the intervention group, and the incidence of hsPDA and complication rates were compared between two groups.</p><p>Nineteen infants who received one course (three doses) of prophylactic ibuprofen in the intervention group and 17 infants in the control group who underwent an echocardiographic examination on the fourth day of life were analyzed. hsPDA was observed in five (26 %) infants in the intervention group and ten (58 %) infants in the control group (p = 0.09). In the intervention group two infants experienced gastrointestinal bleeding two infants had spontaneous intestinal perforation, and two infants developed acute kidney failure. Mean serum ibuprofen level was 28.7 +/- 16.9 mg/L in the intervention group, and there was no correlation between ibuprofen level obtained on the fourth day and ductal closure.</p><p>Oral ibuprofen prophylaxis reduces the rates of hsPDA even it is not statistically significant. The ductal closure rate did not correlate with serum ibuprofen levels. Due to high prevalence of adverse events observed, our data do not support the use of oral ibuprofen for prophylaxis of hsPDA.</p>
Replication Data for: Observation of an environmentally insensitive solid state spin defect in diamond
Engineering coherent systems is a central goal of quantum science. Color centers in diamond are a promising approach, with the potential to combine the coherence of atoms with the scalability of a solid state platform. We report a color center that shows insensitivity to environmental decoherence caused by phonons and electric field noise: the neutral charge state of silicon vacancy (SiV0). Through careful material engineering, we achieve over 80% conversion of implanted silicon to SiV0. SiV0 exhibits spin-lattice relaxation times approaching one minute and coherence times approaching one second. Its optical properties are excellent, with approximately 90% of its emission into the zero-phonon line and near-transform-limited optical linewidths. These combined properties make SiV0 a promising defect for quantum networks
Origins of Diamond Surface Noise Probed by Correlating Single-Spin Measurements with Surface Spectroscopy
The nitrogen-vacancy (NV) center in diamond exhibits spin-dependent fluorescence and long spin coherence times under ambient conditions, enabling applications in quantum information processing and sensing. NV centers near the surface can have strong interactions with external materials and spins, enabling new forms of nanoscale spectroscopy. However, NV spin coherence degrades within 100 nm of the surface, suggesting that diamond surfaces are plagued with ubiquitous defects. Prior work on characterizing near-surface noise has primarily relied on using NV centers themselves as probes; while this has the advantage of exquisite sensitivity, it provides only indirect information about the origin of the noise. Here we demonstrate that surface spectroscopy methods and single-spin measurements can be used as complementary diagnostics to understand sources of noise. We find that surface morphology is crucial for realizing reproducible chemical termination, and use this insight to achieve a highly ordered, oxygen-terminated surface with suppressed noise. We observe NV centers within 10 nm of the surface with coherence times extended by an order of magnitude