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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.

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.

Tetienne J.-P.,CNRS Quantum and Molecular Photonics Laboratory | Rondin L.,CNRS Quantum and Molecular Photonics Laboratory | Spinicelli P.,CNRS Quantum and Molecular Photonics Laboratory | Chipaux M.,Thales Alenia | And 4 more authors.
New Journal of Physics | Year: 2012

Magnetometry and magnetic imaging with nitrogen-vacancy (NV) defects in diamond rely on the optical detection of electron spin resonance (ESR). However, this technique is inherently limited to magnetic fields that are weak enough to avoid electron spin mixing. Here, we focus on the high off-axis magnetic field regime where spin mixing alters the NV defect spin dynamics. We first study, in a quantitative manner, the dependence of the NV defect optical properties on the magnetic field vector B. Magnetic-field-dependent time-resolved photoluminescence (PL) measurements are compared to a seven-level model of the NV defect that accounts for field-induced spin mixing. The model reproduces decreases in (i) ESR contrast, (ii) PL intensity and (iii) excited level lifetime with an increasing off-axis magnetic field. We next demonstrate that these effects can be used to perform all-optical imaging of the magnetic field component |B⊥| orthogonal on the NV defect axis. Using a scanning NV defect microscope, we map the stray field of a magnetic hard disc through both PL and fluorescence lifetime imaging. This all-optical method for high magnetic field imaging at the nanoscale might be of interest in the field of nanomagnetism, where samples producing fields in excess of several tens of milliteslas are typically found. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

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.

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.

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