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Limoges, France

Tombelaine V.,Institute of Photonic Technologies Jena | Bergner G.,Institute of Photonic Technologies Jena | Vater E.,Institute of Photonic Technologies Jena | Schlucker S.,University of Osnabruck | And 6 more authors.
Optics Communications | Year: 2011

Supercontinuum fiber light sources with their extremely wide wavelength spectrum can provide new options for achieving specific wavelength distributions in a very flexible way. Two concepts for the combination of such supercontinuum light sources with a spectrally dispersive optical system and an interactive filter for modulating the light spectrum are discussed. These concepts provide the possibility to achieve laser-like light sources with an almost arbitrary shape of the spectrum, great flexibility in interactive tuning of the spectral properties and covering wavelengths from UV to the infrared range. © 2010 Elsevier B.V. All rights reserved.

Fahs H.,Xlim Institute | Hadjem A.,Orange S.A. | Lanteri S.,French Institute for Research in Computer Science and Automation | Wiart J.,Orange S.A.
IEEE Transactions on Antennas and Propagation | Year: 2011

The great majority of numerical calculations of the specific absorption rate (SAR) induced in human tissues exposed to microwaves are performed using the finite difference time-domain (FDTD) method and voxel-based geometrical models. The straightforward implementation of the method and its computational efficiency are among the main reasons for FDTD being currently the leading method for numerical assessment of human exposure to electromagnetic waves. However, the rather difficult departure from the commonly used Cartesian grid and cell size limitations regarding the discretization of very detailed structures of human tissues are often recognized as the main weaknesses of the method in this application context. In particular, interfaces between tissues where sharp gradients of the electromagnetic field may occur are hardly modeled rigorously in these studies. We present here an alternative numerical dosimetry methodology which is based on a high order discontinuous Galerkin time-domain (DGTD) method and adapted geometrical models constructed from unstructured triangulations of tissue interfaces, and discuss its application to the calculation of the SAR induced in head tissues. © 2011 IEEE.

Courreges F.,Xlim Institute | Absi J.,University of Limoges | Laribi M.A.,University of Poitiers | Arsicault M.,University of Poitiers | Zeghloul S.,University of Poitiers
Proceeding - 2015 IEEE International Conference on Industrial Informatics, INDIN 2015 | Year: 2015

The aim of this work is to improve the safety and control robustness of robots interacting physically with humans by enhancing their contact perception. More specifically in the abdominal area, respiratory motions are clearly influencing the contact dynamics but have not yet been accounted for in the estimation of the contact impedance. We propose here a combined mechanical-respiratory model of impedance along with its on-line identification. Numerical and practical experiments with living subjects validate the identification process and show the relevance in accuracy of accounting for the respiratory beats. © 2015 IEEE.

Bui N.,Xlim Institute | Guiffaut C.,Xlim Institute | Reineix A.,Xlim Institute | Pouliguen P.H.,Directorate General of Armaments
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2015

In this paper, we propose a FDTD(2,4) scheme to reduce numerical dispersion compared to the standard Yee scheme. This scheme is designed to retain a two dimensional stencil in the field update equations. We derive the numerical dispersion equation of this scheme and show its high-phase accuracy at low-grid resolutions. Moreover, the Courant-Friedrichs-Lewy condition (CFL) of this scheme does not decrease the usual standard time-step given by the CFL condition of the Yee scheme. With this scheme, we can model large structures with high accuracy results. © 2015 IEEE.

Labruyere A.,Xlim Institute | Jaffres L.,Xlim Institute | Jaffres L.,Horus Laser S.A.S. | Couderc V.,Xlim Institute
Laser Physics Letters | Year: 2012

We demonstrate a novel method for active and passive Q-switching of a bulk laser source. The mechanism is based on the deflection of laser light through an electric channel of plasma that is temporarily created inside the resonator. The channel of plasma consists of an electric spark in air actuated with a spark gap. It acts as a spatio-temporal prism that momentarily enables the laser light to oscillate resonantly, thus triggering the creation of a laser pulse. Nanosecond pulses from a microchip laser source have been obtained with a limited timing jitter. © 2012 by Astro, Ltd.

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