Laboratoire Aime Cotton
Laboratoire Aime Cotton
Reschechtko S.,Pennsylvania State University |
Hasanbarani F.,Pennsylvania State University |
Hasanbarani F.,University of Tehran |
Akulin V.M.,Laboratoire Aime Cotton |
And 3 more authors.
Neuroscience | Year: 2017
The study explored unintentional force changes elicited by removing visual feedback during cyclical, two-finger isometric force production tasks. Subjects performed two types of tasks at 1 Hz, paced by an auditory metronome. One – Force task – required cyclical changes in total force while maintaining the sharing, defined as relative contribution of a finger to total force. The other task – Share task – required cyclical changes in sharing while keeping total force unchanged. Each trial started under full visual feedback on both force and sharing; subsequently, feedback on the variable that was instructed to stay constant was frozen, and finally feedback on the other variable was also removed. In both tasks, turning off visual feedback on total force elicited a drop in the mid-point of the force cycle and an increase in the peak-to-peak force amplitude. Turning off visual feedback on sharing led to a drift of mean share toward 50:50 across both tasks. Without visual feedback there was consistent deviation of the two force time series from the in-phase pattern (typical of the Force task) and from the out-of-phase pattern (typical of the Share task). This finding is in contrast to most earlier studies that demonstrated only two stable patterns, in-phase and out-of-phase. We interpret the results as consequences of drifts of parameters in a dynamical system leading in particular to drifts in the referent finger coordinates toward their actual coordinates. The relative phase desynchronization is caused by the right–left differences in the hypothesized drift processes, consistent with the dynamic dominance hypothesis. © 2017 IBRO
Nowodzinski A.,CEA Grenoble |
Chipaux M.,Thales Alenia |
Chipaux M.,Laboratoire Aime Cotton |
Chipaux M.,University of Groningen |
And 5 more authors.
Microelectronics Reliability | Year: 2015
We present a novel technique based on an ensemble of Nitrogen-Vacancy (NV) centers of diamond to perform Magnetic Current Imaging (MCI) on an Integrated Circuit (IC). NV centers of diamond permit to measure the three components of the magnetic fields generated by mA range current in an IC structure over a field of 50 × 200 μm with sub-micrometric resolution. Vector measurements allow the use of a more robust algorithm than those used for MCI using GMR or SQUID sensors and it is opening new current reconstruction prospects. Calculated MCI from these measurements shows a very good agreement with theoretical current path. Acquisition time is around 10 s, which is much faster than scanning measurements using Superconducting Quantum Interference Device (SQUID) or Giant Magneto Resistance (GMR). The experimental set-up relies on a standard optical microscope, and the measurements can be performed at room temperature and atmospheric pressure. These early experiences, not optimized for IC, show that NV centers in diamond could become a real alternative for MCI in IC. © 2015 Elsevier Ltd.
Mezei J.Z.,CNRS Laboratory of Waves and Complex Media |
Mezei J.Z.,University Paris - Sud |
Mezei J.Z.,Hungarian Academy of Sciences |
Schneider I.F.,CNRS Laboratory of Waves and Complex Media |
And 4 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012
Multichannel quantum defect theory is used to calculate photoionization cross sections for vibrationally excited diatomic hydrogen. The calculations are based on the state-of-the-art clamped-nuclei potential energy curves and electronic dipole transition moments of Wolniewicz. The calculations indicate that, in contrast to what had been assumed previously, autoionization resonances dominate the cross section. © 2012 American Physical Society.
Nowodzinski A.,CEA Grenoble |
Chipaux M.,Thales Alenia |
Toraille L.,Thales Alenia |
Toraille L.,Ecole Normale Superieure de Lyon |
And 3 more authors.
Microelectronics Reliability | Year: 2015
We present a novel technique based on an ensemble of Nitrogen-Vacancy (NV) centers of diamond to perform Magnetic Current Imaging (MCI) on an Integrated Circuit (IC). NV centers of diamond permit to measure the three components of the magnetic fields generated by mA range current in an IC structure over a field of 50. ×. 200. μm with sub-micrometric resolution. Vector measurements allow the use of a more robust algorithm than those used for MCI using GMR or SQUID sensors and it is opening new current reconstruction prospects. Calculated MCI from these measurements shows a very good agreement with theoretical current path. Acquisition time is around 10. s, which is much faster than scanning measurements using Superconducting Quantum Interference Device (SQUID) or Giant Magneto Resistance (GMR). The experimental set-up relies on a standard optical microscope, and the measurements can be performed at room temperature and atmospheric pressure. These early experiences, not optimized for IC, show that NV centers in diamond could become a real alternative for MCI in IC. © 2015 Elsevier Ltd.
Gucsik A.,Kyoto University |
Gucsik A.,Max Planck Institute for Chemistry |
Nishido H.,Okayama University of Science |
Ninagawa K.,Okayama University of Science |
And 6 more authors.
Microscopy and Microanalysis | Year: 2012
Color centers in selected micro-and nanodiamond samples were investigated by cathodoluminescence (CL) microscopy and spectroscopy at 298 K [room temperature (RT)] and 77 K [liquid-nitrogen temperature (LNT)] to assess the value of the technique for astrophysics. Nanodiamonds from meteorites were compared with synthetic diamonds made with different processes involving distinct synthesis mechanisms (chemical vapor deposition, static high pressure high temperature, detonation). A CL emission peak centered at around 540 nm at 77 K was observed in almost all of the selected diamond samples and is assigned to the dislocation defect with nitrogen atoms. Additional peaks were identified at 387 and 452 nm, which are related to the vacancy defect. In general, peak intensity at LNT at the samples was increased in comparison to RT. The results indicate a clear temperature-dependence of the spectroscopic properties of diamond. This suggests the method is a useful tool in laboratory astrophysics. © 2012 Microscopy Society of America.
Baili G.,Thales Alenia |
Morvan L.,Thales Alenia |
Pillet G.,Thales Alenia |
Bouchoule S.,CNRS Optic of Semiconductor nanoStructures Group |
And 9 more authors.
Journal of Lightwave Technology | Year: 2014
We describe a compact, ultralow noise, and high-power semiconductor laser implemented in a high performances wideband externally modulated optical link. The laser is based on a vertical external cavity surface emitting laser (VECSEL) designed for high-power and low-noise operation. Thanks to a specific design of the gain chip, the half-VCSEL, based on a metamorphic Bragg mirror and a report on a copper substrate, an optical power of 110 mW is obtained at 1.55 μm in the single frequency regime. For low-noise operation, the laser cavity is designed for free-relaxation-oscillations operation, i.e., in the so-called class-A regime. The Class-A VECSEL exhibits a relative intensity noise below -170 dB/Hz over a wide frequency bandwidth, from 300 MHz to 40 GHz, except at the laser free spectral range (20.4 GHz). In the low-frequency range, the laser noise, mainly due to transfer of pump noise to laser noise, goes from -110 dB/Hz at 1 kHz down to -158 dB/Hz at 10 MHz. Two externally modulated optical links are implemented and compared in terms of the RF gain and the noise figure. The first optical link is based on the ultralow noise class-A VECSEL and the second one is based on a low noise class-B DFB laser. Thanks to the outstanding noise properties of the designed VECSEL, the VECSEL-based optical link outperforms the DFB-based one, in particular for frequencies larger than 20 GHz. © 2012 IEEE.
Benredjem D.,Laboratoire Aime Cotton |
Calisti A.,French National Center for Scientific Research |
Mondet G.,Laboratoire Aime Cotton |
Pain J.C.,CEA DAM Ile-de-France |
Gilleron F.,CEA DAM Ile-de-France
Canadian Journal of Physics | Year: 2011
We present recent results on radiative power losses of carbon and gold ions in fusion plasmas. Our approach is based on a detailed calculation, where the atomic database is provided by the MCDF code. A lineshape code, allowing for NLTE ionic populations, was adapted to the calculation of radiative power loss profiles. Because the calculation time is sometimes prohibitive, an alternative approach based on statistical distributions is proposed. This approach involves the first four moments of the radiative power losses. We have focused our attention on carbon and gold. The first element could be present in the ablator in some inertial confinement schemes. The second element is present in holraums and its X-ray emission contributes to the heating in inertial confinement fusion. Finally, opacity calculations are compared to measured transmission in aluminum ions. © 2011 Published by NRC Research Press.
Benard Y.,Laboratoire Aime Cotton |
Benard Y.,French National Center for Scientific Research |
Lopez-Gil N.,University of Murcia |
Legras R.,Laboratoire Aime Cotton |
Legras R.,French National Center for Scientific Research
Journal of Cataract and Refractive Surgery | Year: 2010
Purpose: To study the impact on the subjective depth of field of 4th-order spherical aberration and its combination with 6th-order spherical aberration and analyze the accuracy of image-quality metrics in predicting the impact. Setting: Laboratoire Aimé Cotton, Centre National de la Recherche Scientifique, Université Paris-Sud, Orsay, France. Design: Case series. Methods: Subjective depth of field was defined as the range of defocus at which the target (3 high-contrast letters at 20/50) was perceived acceptable. Depth of field was measured using 0.18 diopter (D) steps in young subjects with the addition of the following spherical aberration values: ±0.3 μm and ±0.6 μm 4th-order spherical aberration with 3.0 mm and 6.0 mm pupils and ±0.3 μm 4th-order spherical aberration with ±0.1 μm 6th-order spherical aberration for 6.0 mm pupils. Results: The addition of ±0.3 and ±0.6 μm 4th-order spherical aberration increased depth of field by 30% and 45%, respectively. The combination of 4th-order spherical aberration and 6th-order spherical aberration of opposite signs increased depth of field more than 4th-order spherical aberration alone (ie, 63%), while the combination of 4th-order spherical aberration and 6th-order spherical aberration of the same signs did not (ie, 24%). Whereas the midpoint of the depth of field could be predicted by image-quality metrics, none was found a good predictor of objectionable depth of field. Conclusion: Subjective depth of field increased when 4th-order spherical aberration and 6th-order spherical aberration of opposite signs were added but could not be predicted with image-quality metrics. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.
Gilleron F.,CEA DAM Ile-de-France |
Pain J.-C.,CEA DAM Ile-de-France |
Porcherot Q.,CEA DAM Ile-de-France |
Bauche J.,Laboratoire Aime Cotton |
Bauche-Arnoult C.,Laboratoire Aime Cotton
High Energy Density Physics | Year: 2011
For plasmas in LTE at moderate or low temperatures (1-50 eV), the statistical approach for calculating emission or absorption spectra may become inaccurate and need improvement to account for the Boltzmann factor in the population of the levels. In this work, corrections to the transition rates are computed by using the moments of emission or absorption zones, which represent the set of levels within a configuration that provide the dominant part of the emissivity (or opacity). Partition functions are also improved by using high-order moments of level energy distributions. Corrections to the statistical models are derived in a non-relativistic framework as a function of these moments, which can be deduced from already published formulas. Numerical comparisons of detailed line-by-line and statistical calculations are presented that clearly illustrate the importance of correcting the models at low temperatures. Thus, these corrections are of great interest for applications such as Warm Dense Matter, LTE photo-absorption experiments where the targets are heated to ∼Te equals 20 eV and astrophysical plasmas. © 2011 Elsevier B.V.
Zegarra J.,Laboratoire Aime Cotton |
Farcy R.,Laboratoire Aime Cotton
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012
The current GPS (Sirf 3) devices do not give the right heading when their speed is less than 10 km/h. This heading is also less reliable when the GPS is used in the big cities where it is surrounded by buildings. Another important problem is that the change of orientation of the visually impaired needs a long delay to be detected by the GPS due to the fact that the GPS must reach certain speed for obtaining the new heading. It can take from 2 seconds to 15 seconds depending on the GPS signal conditions. In order to avoid these problems, we have proposed the use of one GPS coupled to the IMU (inertial measurement unit). This IMU has one 3 axis compass, a one axis gyroscope and one 3 axis accelerometer. With this system, we can update the heading information every second. The user Interface is developed in the Smart Phone which gives the information of heading and distance to the destination. In this paper, we are also going to describe the advantages of using the heading and distance to the final destination, updated every second, to navigate in cities. © 2012 Springer-Verlag.