Dr. Geoffroy Le Touzé Profile

Dr. Geoffroy Le Touzé

at Focused Energy GmbH

SPIE Involvement:

Author

Publications (11)

Proceedings Article | 19 May 2010 Paper

Experimental measurements and finite-element modelling of thermal effects in Yb3+ doped sesquioxide thin disk lasers

Emilie Marmois, Vanessa Cardinali, Geoffroy Le Touzé, Bruno Le Garrec

Proceedings Volume 7721, 77210O (2010) https://doi.org/10.1117/12.853723

KEYWORDS: Disk lasers, Refractor telescopes, Wavefronts, Thermal effects, Modeling, Quantum efficiency, Ceramics, Temperature metrology, Finite element methods, Ytterbium

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Proceedings Article | 12 October 2005 Paper

Progress in the LUCIA project

G. Bourdet, H. Yu, J.-C. Chanteloup, A. Fülöp, C. Dambrine, S. Ferré, S. Le Moal, A. Pichot, G. Le Touzé, Z. Zhao

Proceedings Volume 5958, 595801 (2005) https://doi.org/10.1117/12.622206

KEYWORDS: Crystals, YAG lasers, Diodes, Optical amplifiers, Ytterbium, Amplifiers, Mirrors, Absorption, Distortion, Composites

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Proceedings Article | 27 April 2005 Paper

Overview of the Lucia laser program: toward 100-Joules, nanosecond-pulse, kW averaged power based on ytterbium diode-pumped solid state laser

J.-C. Chanteloup, H. Yu, G. Bourdet, C. Dambrine, S. Ferre, A. Fulop, S. Le Moal, A. Pichot, G. Le Touze, Z. Zhao

Proceedings Volume 5707, (2005) https://doi.org/10.1117/12.588341

KEYWORDS: Diodes, Crystals, Optical amplifiers, Laser damage threshold, Multiplexing, Semiconductor lasers, Mirrors, Oscillators, Thermography, Lasers

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Proceedings Article | 12 April 2005 Paper

Diode pumped Yb:YAG V-shape unstable super Gaussian laser resonators for 10 Hz – 100 joules class laser

A. Fulop, G. Bourdet, J.-C. Chanteloup, C. Dambrine, S. Ferre, S. Le Moal, A. Pichot, G. Le Touze, H. Yu, Z. Zhao

Proceedings Volume 5708, (2005) https://doi.org/10.1117/12.588395

KEYWORDS: Crystals, Diodes, Mirrors, Semiconductor lasers, Oscillators, Ytterbium, Laser resonators, Resonators, Reflectivity, Laser crystals

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Proceedings Article | 23 July 1999 Paper

Pump-induced wavefront distortion in prototypical NIF/LMJ amplifiers: modeling and comparison with experiments

Mark Rotter, Kenneth Jancaitis, Christopher Marshall, Luis Zapata, A. Erlandson, Geoffroy LeTouze, Stephane Seznec

Proceedings Volume 3492, (1999) https://doi.org/10.1117/12.354178

KEYWORDS: Wavefront distortions, Refractive index, Optical amplifiers, Amplifiers, National Ignition Facility, Cladding, Lamps, Adaptive optics, Data modeling, Metals

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Proceedings Article | 23 July 1999 Paper

3D gain modeling of LMJ and NIF amplifiers

Geoffroy LeTouze, Olivier Cabourdin, J. Mengue, Mireille Guenet, Eric Grebot, Stephane Seznec, Kenneth Jancaitis, Christopher Marshall, Luis Zapata, A. Erlandson

Proceedings Volume 3492, (1999) https://doi.org/10.1117/12.354177

KEYWORDS: 3D modeling, Amplifiers, Reflectors, Glasses, National Ignition Facility, Absorption, Lamps, Autoregressive models, Systems modeling, Diamond

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Proceedings Article | 23 July 1999 Paper

Thermal recovery of LMJ amplifiers

Ph. Arnoux, Geoffroy LeTouze, J. Caltagirone, A. Viguie, B. Bicrel, Eric Grebot, Stephane Seznec, Christopher Marshall, Luis Zapata

Proceedings Volume 3492, (1999) https://doi.org/10.1117/12.354179

KEYWORDS: Optical amplifiers, Adaptive optics, 3D modeling, Wavefront distortions, Wavefronts, Thermal modeling, Lamps, Thermography, Laser optics, Convection

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Proceedings Article | 23 July 1999 Paper

Energy storage efficiency and small signal gain measurements in Nd:phosphate amplifiers

Claude Gamache, Denise Descamps, Daniel Husson, Olivier Cabourdin, Geoffroy LeTouze, J. Mengue, Arnold Migus

Proceedings Volume 3492, (1999) https://doi.org/10.1117/12.354189

KEYWORDS: Absorption, Glasses, Luminescence, Amplifiers, Ions, Neodymium, Energy transfer, Optical amplifiers, Spectroscopy, Photons

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Neodynium doped phosphate glass laser has been chosen as the gain medium of large laser facilities devoted to ignition such as NIF or LMJ [1] because it can be cast into a great variety of form and size with excellent homogeneity at relatively low cost. In this respect Megajoules class laser design relies on previous experimental and numerical studies on energy storage and gain capabilities. These parameters are particularly needed as inputs in the modeling of the amplifying stages in order to dimension and caracterize laser systems. Although there is a abondant litterature on Nd:phosphate glass, we found it necessary to make absolute value measurements. We have so developed different experimental scheme based on amplifiers pumped by a laser [2, 3] and by flashlamps [4]. In parallel, we have developed numerical models which take into account the exact configuration of the amplifiers. The main result of these different experiments is that the use of an adjustable parameter (so-called arbitrary quantum yield) is always needed to obtain a good agreement between experimental and numerical results on gain measurements. Whatever method of pumping was used, we had to introduce a quantum yield close to 0.8 [2, 3, 4] which encompasses all unknown loss mechanisms and all hypothesis assumed in the models (section 2). We have analysed the different energy pathways and we put into evidence loss mechanisms correlated to spectroscopic properties of neodymium ions in host glasses. These mechanisms are energy transfer up-conversion [5]and Excited State Absorption (ESA) of both pump and laser radiation (amplified pulse or florescence from the upper laser state) [6, 7]. The two latter processes are correlated to a high population of excitated states, but all of them can significantly affect the energy storage efficiency and the gain capability of these laser systems by depopulating the upper laser level or reducing the state lifetime. These mechanisms have already been reported for some materials such as neodymium doped fluorite host medium [8] or crystals [7, 9]. Surprinsingly enough few works have been published in case of neodymium doped glasses [10]. Our goal in this work, was to identify and quantify each spectroscopic process that could exist in Nd :doped glasses. We report here spectroscopic experiments and the use of absolute characteristic values as new inputs in the modeling of gain capabilities of a Nd :phosphate amplifying stage (section 3). However part of the losses is also due to non spectroscopic factors such as the pumping geometry. For instance, in case of slab transversally-pumped, not taking into account Fresnel reflectivity could be at the origin of strong losses. This is the reason why we have developed in collaboration with the Lawrence Livermore National Laboratory (LLNL), a full 3D ray trace code that we have used to simulate gain measurement (section 4) [11]. Note that this study is of larger interest for NIF-LMJ program since rare earth doped-glasses appear also promising for future broad-band solid-state systems which would be diode-pumped.

Proceedings Article | 8 December 1997 Paper

Effect of amplifier component maintenance on laser system availability and reliability for the U.S. National Ignition Facility

Alvin Erlandson, H. Lambert, Luis Zapata, L. Pedrotti, Doug Larson, Mark Rotter, W. Dallum, Stephane Seznec, Geoffroy LeTouze, Eric Grebot, O. Carbourdin, J. Fornerod, P. Bosch

Proceedings Volume 3047, (1997) https://doi.org/10.1117/12.294297

KEYWORDS: National Ignition Facility, Amplifiers, Reliability, Optical amplifiers, Reflectors, Electrical breakdown, Electrical insulation failure, Lamps, Silver, Laser systems engineering

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Proceedings Article | 8 December 1997 Paper

Three-dimensional ray-trace model for predicting the performance of flashlamp-pumped laser amplifiers

Kenneth Jancaitis, Scott Haney, David Munro, Geoffroy LeTouze, Olivier Cabourdin

Proceedings Volume 3047, (1997) https://doi.org/10.1117/12.294264

KEYWORDS: 3D modeling, Optical amplifiers, Performance modeling, Glasses, Amplifiers, Laser amplifiers, Laser glasses, National Ignition Facility, Plasma, Lamps

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Proceedings Article | 8 December 1997 Paper

Amplifier pumping optimization (in French)

Geoffroy LeTouze, Olivier Cabourdin, Mireille Guenet, J. Mengue, Kenneth Jancaitis, Mark Rotter

Proceedings Volume 3047, (1997) https://doi.org/10.1117/12.294346

KEYWORDS: Lamps, Amplifiers, Lanthanum, Plasma, Reflectors, Atomic force microscopy, Silicon, Testis, Xenon, Cerium

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Showing 5 of 11 publications

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