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Dreau A.,CNRS Quantum and Molecular Photonics Laboratory | Spinicelli P.,CNRS Quantum and Molecular Photonics Laboratory | Maze J.R.,University of Santiago de Chile | Roch J.-F.,University Paris - Sud | And 2 more authors.
Physical Review Letters | Year: 2013

We use the electronic spin of a single nitrogen-vacancy defect in diamond to observe the real-time evolution of neighboring single nuclear spins under ambient conditions. Using a diamond sample with a natural abundance of C13 isotopes, we first demonstrate high fidelity initialization and single-shot readout of an individual C13 nuclear spin. By including the intrinsic N14 nuclear spin of the nitrogen-vacancy defect in the quantum register, we then report the simultaneous observation of quantum jumps linked to both nuclear spin species, providing an efficient initialization of the two qubits. These results open up new avenues for diamond-based quantum information processing including active feedback in quantum error correction protocols and tests of quantum correlations with solid-state single spins at room temperature. © 2013 American Physical Society.


Do M.T.,CNRS Quantum and Molecular Photonics Laboratory | Nguyen T.T.N.,CNRS Quantum and Molecular Photonics Laboratory | Nguyen T.T.N.,Vietnam Academy of Science and Technology | Li Q.,CNRS Quantum and Molecular Photonics Laboratory | And 3 more authors.
Optics Express | Year: 2013

We demonstrate a new 3D fabrication method to achieve the same results as those obtained by the two-photon excitation technique, by using a simple one-photon elaboration method in a very low absorption regime. Desirable 2D and 3D submicrometric structures, such as spiral, chiral, and woodpile architectures, with feature size as small as 190 nm have been fabricated, by using just a few milliwatts of a continuous-wave laser at 532 nm and a commercial SU8 photoresist. Different aspects of the direct laser writing based on ultralow one-photon absorption (LOPA) technique are investigated and compared with the TPA technique, showing several advantages, such as simplicity and low cost. © 2013 Optical Society of America.


Dreau A.,CNRS Quantum and Molecular Photonics Laboratory | Maze J.-R.,University of Santiago de Chile | Lesik M.,University Paris - Sud | Roch J.-F.,University Paris - Sud | Jacques V.,CNRS Quantum and Molecular Photonics Laboratory
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We report a systematic study of the hyperfine interaction between the electron spin of a single nitrogen-vacancy (NV) defect in diamond and nearby 13C nuclear spins, by using pulsed electron-spin resonance spectroscopy. We isolate a set of discrete values of the hyperfine coupling strength ranging from 14 MHz to 400 kHz and corresponding to 13C nuclear spins placed at different lattice sites of the diamond matrix. For each lattice site, the hyperfine interaction is further investigated through nuclear-spin polarization measurements and by studying the magnetic field dependence of the hyperfine splitting. This work provides information that is relevant for the development of nuclear-spin-based quantum register in diamond. © 2012 American Physical Society.


Rondin L.,CNRS Quantum and Molecular Photonics Laboratory | Tetienne J.-P.,CNRS Quantum and Molecular Photonics Laboratory | Tetienne J.-P.,University Paris - Sud | Rohart S.,University Paris - Sud | And 6 more authors.
Nature Communications | Year: 2013

Despite decades of advances in magnetic imaging, obtaining direct, quantitative information with nanometre scale spatial resolution remains an outstanding challenge. Recently, a technique has emerged that employs a single nitrogen-vacancy defect in diamond as an atomic-size magnetometer, which promises significant advances. However, the effectiveness of the technique when applied to magnetic nanostructures remains to be demonstrated. Here we use a scanning nitrogen-vacancy magnetometer to image a magnetic vortex, which is one of the most iconic objects of nanomagnetism, owing to the small size (∼10 nm) of the vortex core. We report three-dimensional, vectorial and quantitative measurements of the stray magnetic field emitted by a vortex in a ferromagnetic square dot, including the detection of the vortex core. We find excellent agreement with micromagnetic simulations, both for regular vortex structures and for higher-order magnetization states. These experiments establish scanning nitrogen-vacancy magnetometry as a practical and unique tool for fundamental studies in nanomagnetism. © 2013 Macmillan Publishers Limited. All rights reserved.


Rondin L.,CNRS Quantum and Molecular Photonics Laboratory | Rondin L.,ETH Zurich | Tetienne J.-P.,CNRS Quantum and Molecular Photonics Laboratory | Tetienne J.-P.,Ecole Normale Superieure de Cachan | And 6 more authors.
Reports on Progress in Physics | Year: 2014

The isolated electronic spin system of the nitrogen-vacancy (NV) centre in diamond offers unique possibilities to be employed as a nanoscale sensor for detection and imaging of weak magnetic fields. Magnetic imaging with nanometric resolution and field detection capabilities in the nanotesla range are enabled by the atomic-size and exceptionally long spin-coherence times of this naturally occurring defect. The exciting perspectives that ensue from these characteristics have triggered vivid experimental activities in the emerging field of 'NV magnetometry'. It is the purpose of this article to review the recent progress in high-sensitivity nanoscale NV magnetometry, generate an overview of the most pertinent results of the last years and highlight perspectives for future developments. We will present the physical principles that allow for magnetic field detection with NV centres and discuss first applications of NV magnetometers that have been demonstrated in the context of nano magnetism, mesoscopic physics and the life sciences. © 2014 IOP Publishing Ltd.


Dreau A.,CNRS Quantum and Molecular Photonics Laboratory | Lesik M.,CNRS Quantum and Molecular Photonics Laboratory | Rondin L.,CNRS Quantum and Molecular Photonics Laboratory | Spinicelli P.,CNRS Quantum and Molecular Photonics Laboratory | And 3 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We report a systematic study of the magnetic field sensitivity of a magnetic sensor consisting of a single nitrogen-vacancy (NV) defect in diamond, by using continuous optically detected electron spin resonance (ESR) spectroscopy. We first investigate the behavior of the ESR contrast and linewidth as a function of the microwave and optical pumping power. The experimental results are in good agreement with a simplified model of the NV defect spin dynamics, leading to an optimized sensitivity around 2μT/√Hz for a single NV defect in a high-purity diamond crystal grown by chemical vapor deposition. We then demonstrate an enhancement of the magnetic sensitivity by one order of magnitude by using a simple pulsed-ESR scheme. This technique is based on repetitive excitation of the NV defect with a resonant microwave π pulse followed by an optimized readout laser pulse, allowing to fully eliminate power broadening of the ESR linewidth. The achieved sensitivity is similar to that obtained by using Ramsey-type sequences, which is the optimal magnetic field sensitivity for the detection of a dc magnetic field. © 2011 American Physical Society.


Ngo H.M.,CNRS Quantum and Molecular Photonics Laboratory | Ledoux-Rak I.,CNRS Quantum and Molecular Photonics Laboratory
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Nanometer-sized metallic colloidal particles with plasmonic resonances in the visible range are widely investigated for their attractive optical properties as sensors, for imaging and cancer treatment. Their second-order nonlinear optical properties are remarkably high. In this work, silver colloidal solutions have been synthesized by a simple and quick method in aqueous solutions with different protective agents (PVA, PVP). The first hyperpolarizability β values of Ag per atom and per particle for nanospheres at 1064 nm have been measured. Silver nanoparticles, which possess intense visible region surface plasmon absorption bands, prove to be excellent nonlinear scatterers. © 2014 SPIE.


Li Q.,CNRS Quantum and Molecular Photonics Laboratory | Do M.T.,CNRS Quantum and Molecular Photonics Laboratory | Ledoux-Rak I.,CNRS Quantum and Molecular Photonics Laboratory | Lai N.D.,CNRS Quantum and Molecular Photonics Laboratory
Optics Letters | Year: 2013

With respect to experimental condition, we have investigated the point spread function of a high numerical aperture objective lens, taking into account the absorption effect of the studied material. By using a material possessing an ultralow one-photon absorption (LOPA) coefficient at the excitation wavelength, the light beam can penetrate deeply inside the material and be tightly focused into a subwavelength spot, almost the same as in the absence of material. Combining tight focusing and ultralow absorption conditions, we show that LOPA-based microscopy is thus capable of three-dimensional imaging and fabrication with long penetration depth up to 300 ìm. As compared to the commonly used two-photon absorption microscope, the LOPA method allows simplification of the experimental setup and also minimization of the photodamaging or bleaching effect of materials. © 2013 Optical Society of America.


Slablab A.,CNRS Quantum and Molecular Photonics Laboratory | Le Xuan L.,CNRS Quantum and Molecular Photonics Laboratory | Zielinski M.,CNRS Quantum and Molecular Photonics Laboratory | De Wilde Y.,ESPCI ParisTech | And 3 more authors.
Optics Express | Year: 2012

We show that a dimer made of two gold nanospheres exhibits a remarkable efficiency for second-harmonic generation under femtosecond optical excitation. The detectable nonlinear emission for the given particle size and excitation wavelength arises when the two nanoparticles are as close as possible to contact, as in situ controlled and measured using the tip of an atomic force microscope. The excitation wavelength dependence of the second-harmonic signal supports a coupled plasmon resonance origin with radiation from the dimer gap. This nanometer-size light source might be used for high-resolution near-field optical microscopy. © 2011 Optical Society of America.


Dumont M.,CNRS Quantum and Molecular Photonics Laboratory
Journal of the Optical Society of America B: Optical Physics | Year: 2011

In the previous paper [J. Opt. Soc. Am. B 26, 1057 (2009)], the theory of photoisomerization optical pumping cycles had been developed for three-dimensional molecules, and the evolution of tensorial properties had been simulated, with a particular attention to symmetry properties. Here different models of angular redistribution are compared-diffusion in the photoisomer or rotation in photoisomerization processes-in the case of axial molecules, with an axial symmetry of fields. The possibility of increasing ?(2), by destroying the anisotropy with a third pumping beam, is studied theoretically and experimentally. The failure of this experiment is explained by the too slow redistribution in DR1-MMA copolymers. While anisotropy measurements are unable to discriminate between the different models, the dynamics of second harmonic generation pleads for memoryless angular redistribution, with a very small probability. © 2011 Optical Society of America.

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