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Author

Jörg Wrachtrup

Bio: Jörg Wrachtrup is an academic researcher from University of Stuttgart. The author has contributed to research in topics: Diamond & Photon. The author has an hindex of 87, co-authored 386 publications receiving 30259 citations. Previous affiliations of Jörg Wrachtrup include Centre national de la recherche scientifique & Technical University of Berlin.
Topics: Diamond, Photon, Qubit, Quantum sensor, Vacancy defect


Papers
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Journal ArticleDOI
02 Oct 2008-Nature
TL;DR: This work shows how magneto-optical spin detection can be used to determine the location of a spin associated with a single nitrogen-vacancy centre in diamond with nanometre resolution under ambient conditions, and demonstrates the use of a single diamond spin as a scanning probe magnetometer to map nanoscale magnetic field variations.
Abstract: Magnetic resonance imaging and optical microscopy are key technologies in the life sciences. For microbiological studies, especially of the inner workings of single cells, optical microscopy is normally used because it easily achieves resolution close to the optical wavelength. But in conventional microscopy, diffraction limits the resolution to about half the wavelength. Recently, it was shown that this limit can be partly overcome by nonlinear imaging techniques, but there is still a barrier to reaching the molecular scale. In contrast, in magnetic resonance imaging the spatial resolution is not determined by diffraction; rather, it is limited by magnetic field sensitivity, and so can in principle go well below the optical wavelength. The sensitivity of magnetic resonance imaging has recently been improved enough to image single cells, and magnetic resonance force microscopy has succeeded in detecting single electrons and small nuclear spin ensembles. However, this technique currently requires cryogenic temperatures, which limit most potential biological applications. Alternatively, single-electron spin states can be detected optically, even at room temperature in some systems. Here we show how magneto-optical spin detection can be used to determine the location of a spin associated with a single nitrogen-vacancy centre in diamond with nanometre resolution under ambient conditions. By placing these nitrogen-vacancy spins in functionalized diamond nanocrystals, biologically specific magnetofluorescent spin markers can be produced. Significantly, we show that this nanometre-scale resolution can be achieved without any probes located closer than typical cell dimensions. Furthermore, we demonstrate the use of a single diamond spin as a scanning probe magnetometer to map nanoscale magnetic field variations. The potential impact of single-spin imaging at room temperature is far-reaching. It could lead to the capability to probe biologically relevant spins in living cells.

1,814 citations

Journal ArticleDOI
TL;DR: Here, it is demonstrated the synthesis and application of ultrapure isotopically controlled single-crystal chemical vapour deposition (CVD) diamond with a remarkably low concentration of paramagnetic impurities, and single electron spins show the longest room-temperature spin dephasing times ever observed in solid-state systems.
Abstract: As quantum mechanics ventures into the world of applications and engineering, materials science faces the necessity to design matter to quantum grade purity. For such materials, quantum effects define their physical behaviour and open completely new (quantum) perspectives for applications. Carbon-based materials are particularly good examples, highlighted by the fascinating quantum properties of, for example, nanotubes or graphene. Here, we demonstrate the synthesis and application of ultrapure isotopically controlled single-crystal chemical vapour deposition (CVD) diamond with a remarkably low concentration of paramagnetic impurities. The content of nuclear spins associated with the (13)C isotope was depleted to 0.3% and the concentration of other paramagnetic defects was measured to be <10(13) cm(-3). Being placed in such a spin-free lattice, single electron spins show the longest room-temperature spin dephasing times ever observed in solid-state systems (T2=1.8 ms). This benchmark will potentially allow observation of coherent coupling between spins separated by a few tens of nanometres, making it a versatile material for room-temperature quantum information processing devices. We also show that single electron spins in the same isotopically engineered CVD diamond can be used to detect external magnetic fields with a sensitivity reaching 4 nT Hz(-1/2) and subnanometre spatial resolution.

1,751 citations

Journal ArticleDOI
27 Jun 1997-Science
TL;DR: In this article, the fluorescence of individual nitrogen-vacancy defect centers in diamond was observed with room-temperature scanning confocal optical microscopy, and the centers were photostable, showing no detectable change in their fluorescence emission spectrum as a function of time.
Abstract: The fluorescence of individual nitrogen-vacancy defect centers in diamond was observed with room-temperature scanning confocal optical microscopy. The centers were photostable, showing no detectable change in their fluorescence emission spectrum as a function of time. Magnetic resonance on single centers at room temperature was shown to be feasible. The magnetic resonance spectra revealed marked changes in zero-field splitting parameters among different centers. These changes were attributed to strain-induced differences in the symmetry of the centers.

1,609 citations

Journal ArticleDOI
TL;DR: In this paper, the physics of the nitrogen vacancy and other defect centers from the perspective of single defect center spectroscopy were discussed, where the electron spin wave function hyperfine coupling to close nuclei leads to a splitting in the spectrum which allows for optically detected electron nuclear double resonance.
Abstract: The nitrogen vacancy and some nickel related defects in diamond can be observed as single quantum systems in diamond by their fluorescence. The fabrication of single colour centres occurs via generation of vacancies or via controlled nitrogen implantation in the case of the nitrogen vacancy (NV) centre. The NV centre shows an electron paramagnetic ground and optically excited state. As a result electron and nuclear magnetic resonance can be carried out on single defects. Due to the localized nature of the electron spin wavefunction hyperfine coupling to nuclei more than one lattice constant away from the defect as dominated by dipolar interaction. As a consequence the coupling to close nuclei leads to a splitting in the spectrum which allows for optically detected electron nuclear double resonance. The contribution discusses the physics of the NV and other defect centre from the perspective of single defect centre spectroscopy.

837 citations

Journal ArticleDOI
TL;DR: Density matrix tomography of the CROT gate shows that the gate fidelity achieved in the experiments is up to 0.9, good enough to be used in quantum algorithms.
Abstract: Rabi nutations of a single nuclear spin in a solid have been observed. The experiments were carried out on a single electron and a single 13C nuclear spin of a single nitrogen-vacancy defect center in diamond. The system was used for implementation of quantum logical NOT and a conditional two-qubit gate (CROT). Density matrix tomography of the CROT gate shows that the gate fidelity achieved in our experiments is up to 0.9, good enough to be used in quantum algorithms.

710 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability as discussed by the authors, and its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability.
Abstract: The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light-emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state-of-the-art in this emerging field.

6,863 citations