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1. First on-sky interference fringes at 810 nm with the CHARA array using servo controlled hectometric outdoor fibre links.

Author

Magri, Julie, Grossard, Ludovic, Reynaud, François, Fabert, Marc, Lehmann, Lucien, Delage, Laurent, Ligon, Robert, Vargas, Norm, Majoinen, Olli, Brummelaar, Theo ten, Farrington, Christopher D, Scott, Nicholas J, Anugu, Narsireddy, Schaefer, Gail, Gies, Douglas, Woods, Craig, Golden, Steve, Castillo, Victor, Anderson, Matt, and Krawczyk, Rodolphe

Subjects
DELAY lines, SIGNAL-to-noise ratio, ASTRONOMY, INTERFEROMETRY, FIBERS
Abstract

In the framework of the ALOHA (Astronomical Light Optical Hybrid Analysis) project, we have implemented a fibre-linked interferometer connecting two telescopes of the CHARA (Center for High Angular Resolution Astronomy) array to the recombination beam facility using servo controlled hectometric outdoor fibres (240 m). During two consecutive nights, on-sky fringes at 810 nm were recorded on the star Vega (mag 0), with servo control of the fibre lengths. The optical path difference was set close to zero using internal fringes found before the on-sky observations. The repeatability of the delay line position offset between internal and on-sky fringes was less than 0.2 mm. The efficiency of the servo control systems has been demonstrated, leading to an enhancement of the signal-to-noise ratio from 68.9 with the servo off to 91.6 with the servo on. This result is a cornerstone for the ALOHA project goal of interferometry at 3.5  |$\mu$| m and a seminal step for the future kilometric infrared fibre-linked interferometer at CHARA. [ABSTRACT FROM AUTHOR]

Published
2025
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2. First experimental demonstration of temporal hypertelescope operation with a laboratory prototype

Author

Bouyeron, Laurent, Olivier, Serge, Delage, Laurent, Reynaud, François, Armand, Paul, Bousquet, Elsa, and Benoist, Joel

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

In this paper, we report the first experimental demonstration of a Temporal HyperTelescope (THT). Our breadboard including 8 telescopes is firstly tested in a manual cophasing configuration on a 1D object. The Point Spread Function (PSF) is measured and exhibits a dynamics in the range of 300. A quantitative analysis of the potential biases demonstrates that this limitation is related to the residual phase fluctuation on each interferometric arm. Secondly, an unbalanced binary star is imaged demonstrating the imaging capability of THT. In addition, 2D PSF is recorded even if the telescope array is not optimized for this purpose., Comment: Accepted for publication in MNRAS. 11 pages, 25 figures

Published
2010
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7. Optimization of a one dimensional hypertelescope for a direct imaging in astronomy

Author

Armand, Paul, Benoist, JoeL, Bousquet, Elsa, Delage, Laurent, Olivier, Serge, and Reynaud, FrancOis

Subjects
Extrasolar planets, Astronomy, Business, Business, general, Business, international
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2008.02.002 Byline: Paul Armand (a), Joel Benoist (a), Elsa Bousquet (a), Laurent Delage (b), Serge Olivier (b), Francois Reynaud (b) Keywords: Nonlinear programming; Constrained optimization; High contrast imaging; Exoplanet; Hypertelescope; Astronomical technique; Optical systems Abstract: We describe an application of nonlinear optimization in interferometric optical astronomy. The aim is to find the relative positions of the output pupils and the modulus of the beams through each pupil of a linear array of telescopes in order to design an instrument capable of imaging exoplanets. The problem is modelized under the form of a semi-infinite nonlinear minimization problem. The model problem is transformed by a simple discretization into a minimization problem with a finite number of constraints, then it is solved by using a minimization solver. Numerical experiments are reported. Author Affiliation: (a) XLIM UMR 6172, Departement Maths Informatique, Programme Transverse IRO, CNRS et Universite de Limoges, France (b) XLIM, Departement Photonique, Programme Transverse IRO, France Article History: Received 16 May 2007; Accepted 1 February 2008

Published
2009
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8. Influence of the input-stage architecture on the in-laboratory test of a mid-infrared interferometer: application to the ALOHA up-conversion interferometer in the L band

Author

Magri, Julie, Lehmann, Lucien, Grossard, Ludovic, Delage, Laurent, Reynaud, François, Chauvet, Mathieu, Bassignot, Florent, Krawczyk, Rodolphe, Le Duigou, Jean-Michel, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Thales Alenia Space (Thales), and Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics]
Abstract

International audience; In the framework of the Astronomical Light Optical Hybrid Analysis (ALOHA) laboratory mid-infrared (MIR) up-conversion fibred interferometer in the L band, we report on the influence of the input-stage architecture. Using an amplitude division set-up in the visible or near-infrared is a straightforward choice in most cases. In the MIR context, the results are slightly different and we show that a wavefront division set-up is needed. These in-laboratory principle experiments allow us to measure a reliable 88 per cent instrumental contrast with high flux and to obtain fringes from faint sources at 3.5 μm with a spectral bandwith of 37 nm converted to 817 nm. An equivalent limiting L-band magnitude around 3.9, equivalent to 3.0 fW nm -1, could be demonstrated on 1 m class telescopes. This opens the possibility of planning future on-sky tests at the Center for High Angular Resolution Astronomy (CHARA) array and of predicting the performance attained.

Published
2021

9. MAFL experiment: development of photonic devices for a space-based multiaperture fiber-linked interferometer

Author

Olivier, Serge, Delage, Laurent, Reynaud, Francois, Collomb, Virginie, Trouillon, Michel, Grelin, Jerome, Schanen, Isabelle, Minier, Vincent, Broquin, Jean-Emmanuel, Ruilier, Cyril, and Leone, Bruno

Subjects
Interferometers -- Usage, Images, Optical -- Research, Fiber optics -- Research, Fiber optics, Astronomy, Physics
Abstract

We present a three-telescope space-based interferometer prototype dedicated to high-resolution imaging. This project, named multiaperture fiber-linked interferometer (MAFL), was founded by the European Space Agency. The aim of the MAFL project is to propose, design, and implement for the first time to the best of our knowledge all the optical functions required for the global instrument on the same integrated optics (IO) component for controlling a three-arm interferometer and to obtain reliable science data. The coherent transport from telescopes to the IO component is achieved by means of highly birefringent optical fiber. The laboratory bench is presented, and the results are reported allowing us to validate the optical potentiality of the IO component in this frame. The validation measurements consist of the throughput of this optical device, the performances of metrological servoloop, and the instrumental contrasts and phase closure of the science fringes. OCIS codes: 060.2430, 130.0130, 070.6110, 120.3180, 350.1260, 350.6090.

Published
2007

10. Three-beam photonic crystal fiber imaging interferometer

Author

Vergnole, Sebastien, Delage, Laurent, and Reynaud, Francois

Subjects
Optical instruments -- Research, Interferometers -- Usage, Interferometers -- Analysis, Fiber optics -- Equipment and supplies, Fiber optics -- Research, Fiber optics -- Structure, Astronomy, Physics
Abstract

Some varieties of photonic crystal fiber (PCF) have huge potential for high-resolution imaging in astronomy. They allow us to operate in a single-mode regime over a wide bandwidth keeping a high transmission level. Thus they may be used to carry wide spectral light over hundreds of meters. We report the implementation of what we believe to be the first three-beam interferometer fitted with PCF arms. This configuration is needed to achieve high-resolution imaging. A full description of the experimental setup is given, and closure phase measurements achieved over a 1 [micro]m bandwidth are also presented. With a pointlike source, the theoretical closure phase is expected to be 0 rad. Experimentally, a mean closure phase of 0.01 rad has been measured with a 0.07 rad standard deviation. These results confirm that PCF should be used in an astronomical context. OCIS codes: 060.2430, 120.3180, 350.1260.

Published
2006

11. Test of photonic crystal fiber in broadband interferometry

Author

Vergnole, Sebastien, Delage, Laurent, Reynaud, Francois, Labonte, Laurent, Roy, Philippe, Melin, Gilles, and Gasca, Laurent

Subjects
Waveguides -- Research, Optics -- Research, Photonics -- Research, Photonics -- Technology application, Technology application, Astronomy, Physics
Abstract

Photonic crystal fibers (PCFs) are microstructured waveguides that are used in metrology, nonlinear optics, and coherent tomography. PCF studies are focused mainly on the improvement of dispersion properties and wide spectral single-mode operating domains. Consequently, in the astronomical context this kind of fiber is a good candidate for use in the design of a fiber-linked version of a stellar interferometer for aperture synthesis. We discuss the potential of these fibers to take advantage of wide spectral single-mode operation. We propose an experimental setup that acts as a two-beam interferometer that uses PCFs to measure fringe contrast at four wavelengths (670,980, 1328, and 1543 nm), which correspond to the R, I, J, and H astronomical bands, respectively, with the same couple of PCFs. For this purpose we use, for the first time to our knowledge, a piezoelectric PCF optical path modulator. OCIS codes: 060.2430, 120.3180, 350.1270.

Published
2005

12. Influence of the antenna diagram on a stellar interferometer that is suffering from telescope-pointing errors

Author

Longueteau, Emmanuel, Delage, Laurent, and Reynaud, Francois

Subjects
Interferometers -- Usage, Antenna arrays -- Influence, Data entry -- Methods, Astronomy, Physics
Abstract

We report our experimental investigations of the influence of differential telescope-pointing errors on data corruption in an optical stellar interferometer. This effect was investigated theoretically as a function of the telescope antenna diagram, which depends on the aperture diameter. Using a laboratory breadboard consisting of a three-telescope array, we carried out the experiments with various aperture diameters and complex objects. The results matched the simulation and demonstrate that, when there is no error in pointing, a large aperture size induces correctible error but that, with a pointing error, data corruption becomes critical. In both cases, the larger the apertures, the more corrupt the data. OCIS codes: 060.2360, 060.2430, 070.6020, 110.5100, 110.6770, 120.3180.

Published
2002

13. Influence of the input-stage architecture on the in-laboratory test of a mid-infrared interferometer: application to the ALOHA up-conversion interferometer in the L band

Author

Magri, Julie, primary, Lehmann, Lucien, additional, Grossard, Ludovic, additional, Delage, Laurent, additional, Reynaud, François, additional, Chauvet, Mathieu, additional, Bassignot, Florent, additional, Krawczyk, Rodolphe, additional, and Le Duigou, Jean-Michel, additional

Published
2020
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15. ALOHA—Astronomical Light Optical Hybrid Analysis

Author

Lehmann, Lucien, Darré, Pascaline, Szemendera, Ludovic, Gomes, Jean-Thomas, Baudoin, Romain, Ceus, Damien, Brustlein, Sophie, Delage, Laurent, Grossard, Ludovic, Reynaud, François, Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic
Abstract

International audience; This paper gives an overview of the Astronomical Light Optical Hybrid Analysis (ALOHA) project dedicated to investigate a new method for high resolution imaging in mid infrared astronomy. This proposal aims to use a non-linear frequency conversion process to shift the thermal infrared radiation to a shorter wavelength domain compatible with proven technology such as guided optics and detectors. After a description of the principle, we summarise the evolution of our study from the high flux seminal experiments to the latest results in the photon counting regime.

Published
2018
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18. Towards a mid-infrared L band up-conversion interferometer: first on-sky sensitivity test on a single arm

Author

Lehmann, Lucien, primary, Grossard, Ludovic, additional, Delage, Laurent, additional, Reynaud, François, additional, Chauvet, Mathieu, additional, Bassignot, Florent, additional, Martinache, Frantz, additional, Morand, Frédéric, additional, Rivet, Jean-Pierre, additional, Schmider, François-Xavier, additional, and Vernet, David, additional

Published
2019
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19. First fringes on the sky with an upconversion interferometer tested on a telescope Array

Author

Darré, Pascaline, Delage, Laurent, Grossard, Ludovic, Reynaud, François, Baudoin, Romain, Gomes, Jean-Thomas, Scott, Nicholas J, Sturmann, Judit, Farrington, Chris, Ten Brummelaar, Theo, Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Novae, Center for High Angular Resolution Astronomy (CHARA), Georgia State University, and University System of Georgia (USG)-University System of Georgia (USG)

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Astrophysics::Galaxy Astrophysics
Abstract

International audience; The Astronomical Light Optical Hybrid Analysis (ALOHA) project investigates the combined use of a telescope array interferometer and nonlinear optics to propose a new generation of instruments dedicated to high resolution imaging for infrared astronomy. The nonlinear process of optical frequency conversion transfers the astronomical light to a shorter wavelength domain. Here, we report on the first fringes obtained on the sky with the prototype operated at 1.55 µm in the astronomical H band and implemented on the Center for High Angular Resolution Astronomy (CHARA) telescope array. This seminal result allows us to foresee a future extension to the challenging mid-infrared spectral domain. PACS numbers: 42.65.Ky, 42.50.Ex, 07.60.Ly, 42.65.Wi, 95.55.Cs Many astronomical studies in the optical domain, such as Active Galactic Nuclei, Young Stellar Objects, formation and evolution of planetary systems require very accurate information in the order of milli-arcseconds. To achieve this level of performance, astronomical instruments have evolved from monolithic structures, with a maximum aperture diameter smaller than 10 m, to telescope arrays with a set of apertures separated by several hundred meters. In this operating framework, the observation of an astrophysical target does not produce classical images, but involves the analysis of the similarity between the optical waves collected by each elementary telescope through intensity [1, 2] or field correlation [3].

Published
2016
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22. Laboratory imaging stellar interferometer with fiber links

Author

Delage, Laurent, Reynaud, Francois, and Lannes, Andre

Subjects
Imaging systems -- Analysis, Fiber optics -- Analysis, Astronomy -- Equipment and supplies, Interferometers -- Analysis, Astronomy, Physics
Abstract

We report on the implementation of an end-to-end imaging demonstrator to validate the concept of optical fiber use in high-resolution aperture synthesis in astronomy. As the coherent transport of light has been conclusively investigated, this study is focused primarily on the accuracy and reliability of the experimental data. In the framework of the European Space Agency project Optical Aperture Synthesis Technologies (OAST), the telescope array's complexity is minimized such that a realistic concept for a future space mission can be proposed. The reconstructed images are obtained by use of a particular self-calibration procedure that was designed to process the visibility contrast and the related weak phase information (one phase closure for each visibility triplet). [C] 2000 Optical Society of America OCIS codes: 070.6020, 100.3020, 110.2350, 110.5100, 120.3930, 120.3180, 120.5050, 120.4640.

Published
2000

26. Optimization applied to the design of an array of telescopes with high sensitivity imaging

Author

Armand, Paul, Benoist, Joël, Delage, Laurent, Reynaud, François, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), DMI (XLIM-DMI), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and PHOTONIQUE (XLIM-PHOTONIQUE)

Subjects
Semi-infinite optimization, Optical interferometry, Nonlinear optimization, Astrophysics::Instrumentation and Methods for Astrophysics, [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC]
Abstract

International audience; The direct observation of tiny little object, like exoplanets, is a challenging problem in optical astronomy. The design of an instrument with a strongly high resolution and a huge dynamics involve the assembling of several telescopes under the form of an array and the use of optical interferometric technology. This design of a so-called hypertelescope can be modelized under the form of nonlinear semi-infinite optimization problem those solutions are the positions and the diameter of the telescopes into the array. We report on some theoretical results and numerical experiments to solve this difficult problem.

Published
2014

27. Present status on the implementation of a up-conversion interferometer on CHARA

Author

Reynaud, François, Delage, Laurent, Grossard, Ludovic, Baudoin, Romain, Gomes, Jean-Thomas, PHOTONIQUE (XLIM-PHOTONIQUE), XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], ComputingMilieux_MISCELLANEOUS, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract

International audience

Published
2013

28. Progress on non-linear SFG use for high resolution imaging

Author

Gomes, Jean-Thomas, Grossard, Ludovic, Ceus, Damien, Vergnole, Sébastien, Delage, Laurent, Reynaud, François, Herrmann, Harald, Sohler, Wolfgang, PHOTONIQUE (XLIM-PHOTONIQUE), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), HORIBA France SAS [Villeneuve d'Ascq], HORIBA Scientific [France], Angewandte Physik, and Universität Paderborn (UPB)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], ComputingMilieux_MISCELLANEOUS, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract

International audience

Published
2012

29. Application of frequency conversion of starlight to high-resolution imaging interferometry. On-sky sensitivity test of a single arm of the interferometer

Author

Ceus, Damien, Reynaud, François, Woillez, J., Lai, Olivier, Delage, Laurent, Grossard, Ludovic, Baudoin, Romain, Gomes, Jean-Thomas, Bouyeron, Laurent, Herrmann, Harald, Sohler, Wolfgang, PHOTONIQUE (XLIM-PHOTONIQUE), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Angewandte Physik, and Universität Paderborn (UPB)

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics
Abstract

International audience; We investigate the sensitivity of frequency conversion of starlight using a non-linear optical sum frequency process. This study is being carried out in the context of future applications of optical interferometry dedicated to high-resolution imaging. We have implemented a complete experimental chain from telescope to detector. The starlight frequency is shifted from the infrared to the visible using an optically non-linear crystal. To fulfil the requirements of interferometry, our experimental setup uses spatially single-mode and polarization maintaining components. Due to the small size of the collecting aperture (8 inches Celestron C8) with a 3 nm spectral bandwidth, on-sky tests were performed on bright stars in the H band. The detection was achieved in a true photon counting operation, using synchronous detection. Betelgeuse (HMag =−3.9), Antares (HMag =−3.6) and Pollux (HMag =−1) were successfully converted and detected in visible light. Despite the low transmission of our experiment, our results prove that the efficiency of frequency conversion offers sufficient sensitivity for future interferometric applications.

Published
2012
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30. Asservissement et cophasage des antennes synthétiques dédiées à l'imagerie haute résolution pour l'astronomie

Author

Reynaud, François, Bouyeron, Laurent, Ceus, Damien, Delage, Laurent, Grossard, Ludovic, Gomes, Jean-Thomas, Baudoin, Régis, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Maury, Véronique

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2011

31. Workshop hypertelescope Nice

Author

Reynaud, François, Bouyeron, Laurent, Ceus, Damien, Delage, Laurent, Grossard, Ludovic, Gomes, Jean-Thomas, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Maury, Véronique

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2011

32. Two new proposals for high resolution imaging in astronomy: Parametric interferometers and temporal hypertelescopes

Author

Reynaud, François, Bouyeron, Laurent, Ceus, Damien, Delage, Laurent, Grossard, Ludovic, Gomes, Jean-Thomas, Tonello, Alessandro, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Maury, Véronique

Abstract

National audience; High resolution stellar interferometers are very powerful and efficient instruments to get a better knowledge of our Universe through direct imaging or spatial coherence. Many important results are currently obtained with interferometers such as Keck telescopes or VLTI. For 30 years, we have developed at Limoges lab a set of new techniques to simplify the architecture of a telescope array dedicated to high resolution imaging. In a first step, I will present you a tutorial on the current status of high resolution imaging techniques mainly based on the coherence analysis. Second, I will explain how we intend to use non-linear optics in this field. Our team proposes to explore the possibility of using non-linear optical techniques to avoid lots of technical difficulties related to infrared optics (components transmission, thermal noises, thermal cooling,...). This is a promising alternative technique for the detection of infrared optical signals. Indeed, we have experimentally demonstrated that sum frequency generation in a non-linear crystal (PPLN) does not result in an additional bias on the interferometric data provided by a stellar interferometer up to the photon counting regime. Last, I will describe a new kind of instrument allowing to provide direct images. The temporal hypertelescope is a new version of spatial hypertelescope proposed by A. Labeyrie. Our temporal version simplifies the implementation through a transposition from the spatial to the temporal domain. The experimental demonstration has been achieved with an 8-telescope laboratory prototype. A servo-control system has been implemented using a genetic algorithm and a phase diversity technique allowing to reach a $10^3-10^4$ dynamics. At the present time, we are studying noise limits up to the photon counting regime.

Published
2011

33. Using up-conversion interferometers for high resolution imaging. Proposal for a collaboration with CHARA

Author

Reynaud, François, Ceus, Damien, Delage, Laurent, Grossard, Ludovic, Gomes, Jean-Thomas, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Maury, Véronique

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

37. First experimental demonstration of temporal hypertelescope operation with laboratory prototype

Author

Bouyeron, Laurent, Olivier, Serge, Delage, Laurent, Reynaud, François, Armand, Paul, Bousquet, Elsa, Benoist, Joël, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), DMI, and Vieceli, Yolande

Subjects
[SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2010

38. First experimental demonstration of temporal hypertelescope operation

Author

Bouyeron, Laurent, Olivier, Serge, Delage, Laurent, Reynaud, François, Maury, Véronique, PHOTONIQUE, XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2010

39. Utilisation de la conversion paramétrique en somme de fréquence dans un interféromètre d'imagerie haute résolution pour astronomie

Author

Reynaud, François, Brustlein, Sophie, del Rio, Louis, Tonello, Alessandro, Delage, Laurent, Ceus, Damien, Grossard, Ludovic, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Lebraud, Sophie, and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

40. Nonlinear optimization applied to the design of an array of telescopes for direct imaging in astronomy

Author

Armand, Paul, Benoist, Joël, Bousquet, Elsa, Delage, Laurent, Olivier, Serge, Reynaud, François, Lebraud, Sophie, DMI, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), PHOTONIQUE, and Transverse IRO

Subjects
[SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

41. Using up-conversion interferometer for high resolution imaging. Up to the photon counting limit?

Author

Reynaud, François, Ceus, Damien, Delage, Laurent, Tonello, Alessandro, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Lebraud, Sophie

Subjects
[SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

42. Laboratory Demonstrattion of an infrared-to-visible up –conversion interferometer for spatial coherence analysis

Author

Brutlein, S., Del Rio, Louis, Tonello, Alessandro, Delage, Laurent, Reynaud, François, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Lebraud, Sophie

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

43. Imagerie optique haute résolution pour l'astronomie.Développement technologique et méthodes prospectives

Author

Reynaud, François, Delage, Laurent, Tonello, Alessandro, Oliver, S., del Rio, Louis, Brustlein, Sophie, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Maury, Véronique

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2008

44. First demonstration of a temporal coherence analysis throught a parametric interferometer

Author

Del Rio, Louis, Ribiere, M., Delage, Laurent, Reynaud, François, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Lebraud, Sophie

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

46. The MAFL experiment : development of photonic devices for a space-based Multi-Aperture Fiber Linked Interferometer

Author

Olivier, Serge, Delage, Laurent, Reynaud, François, Collomb, V., Trouillon, M., Grelin, J., Schanen, I., Minier, V., Broquin, J.E., Ruilier, C., Leone, B., PHOTONIQUE, XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

47. Temporal hypertélescope ; Up conversion and coherence transfer for high resolution imaging

Author

Reynaud, François, Delage, Laurent, Tonello, Alessandro, Olivier, Serge, del Rio, Louis, Brustlein, Sophie, PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Maury, Véronique

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2006

49. Rôle du Semis direct sur couverture végétale -SCV dans la protection de l'environnement [Texte intégral]

Author

Khaledian, Mohammadreza, Mailhol, Jean-Claude, Ruelle, Pierre, Lahmar, Rabah, Rollin, Dominique, Rosique, Patrick, and Delage, Laurent

Subjects
F07 - Façons culturales, F08 - Systèmes et modes de culture, P01 - Conservation de la nature et ressources foncières
Abstract

L'agriculture conventionnelle avec le brûlage des pailles, le labour et le travail intensif du sol produit des émissions directes supplémentaires de Co2 vers l'atmosphère et réduit sa fixation par le sol. Le déstockage du carbone du sol et contribue au réchauffement global de la planète. Un ensemble de techniques nouvelles est proposé pour pérenniser l'activité agricole dans ses milieux physiques, sociaux, économiques et environnementaux. Dans cet ensemble se trouvent notamment les Techniques Culturales Simplifiées -TCS qui visent une meilleure conservation des sols. Les TCS permettent de mieux gérer le sol en altérant au minimum sa composition, sa structure, sa biodiversité naturelle et le préservent de l'érosion et des dégradation. Cette protection est encore meilleure lorsque le sol est protégé par une couverture comme dans le cas du Semis direct sur Couverture Végétale (SCV). Cette technique est en effet fondée sur le maintien d'un couvert végétal permanent (vivant ou mort) et l'emploi du semis direct. Dans le cadre de développement de nouvelles techniques innovantes, le Cirad, le Cemagref et l'Ird ont associé leurs efforts scientifiques dans un Programme Commun de Systèmes Irrigués -PCSI. Ils s'intéressent aux possibilités d'adoption de nouveaux itinéraires techniques fondés sur le SCV dans le sud de la France. L'expérimentation a été réalisée sur une parcelle expérimentale du Cemagref d'environ 3 ha, située à Lavalette, au Nord de Montpellier (43° 40¿N, 3° 50¿E; altitude 30 m). Le climat est de type méditerranéen. Les précipitations moyennes annuelles sont de 750 mm. Le maïs, le sorgho et blé dur sont cultivés pendant 2 ans pour chacune des cultures. Deux séries de traitements sont mises en place: des traitements en SCV et des traitements avec labour et itinéraire technique traditionnel. Pour le maïs et le sorgho en SCV une couverture est semée puis détruite avant l'installation de la culture. Pour le blé dur, il y n'a pas eu de couverture semée mais le paillis des années précèdent demeure. Cette étude présente les résultats obtenus dans un essai de 2000 à 2006, pour les deux système. Les observations retenues sont: le rendement de culture, le bilan de l'eau et d'azote, l'évolution de la matière organique (MOS), N et C du sol et certains éléments majeurs. Le SCV permet de réduire l'apport d'eau et les pertes d'azote. Une augmentation générale des stocks de MOS, C, et N du sol est observée avec la pratique de SCV. La séquestration du Carbone (réduction de l'émission de gaz à effet de serre avec stockage dans le sol) et l'augmentation de la MOS a un effet positif et direct sur l'amélioration des propriétés du sol qui sont considérés comme bénéfiques pour la microfaune et l'environnement. (Texte intégral)

Published
2006

50. Interferometric coupling of the keck telescopes with single-mode fibers

Author

Perrin, G., Woillez, J., Lai, Olivier, Guerin, J., Kotani, T., Wizinowich, P.L., Le Mignant, D., Hrynevych, M., Gathright, J., Lena, P., Chaffee, F., Vergnole, S., Delage, Laurent, Reynaud, François, Adamson, A.-J., Berthod, Carole, Brient, B., Collin, C., Cretenet, J., Dauny, F., Deleglise, C., Fédou, Pierre, Goeltzenlichter, T., Hulin, R., Marlot, C., Marteaud, M., Melse, B.T., Reess, M., Rigaut, F., Ziegler, D., PHOTONIQUE, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Lebraud, Sophie

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2006

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