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(122) Production(s) de VACHER R.
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Eliminating the broadening by finite aperture in Brillouin spectroscopy 
Auteur(s): Vialla R., Ruffle B., Guimbretiere Guillaume, Vacher R.
(Article) Publié:
Review Of Scientific Instruments, vol. 82 p.113110 (2011)
Texte intégral en Openaccess : 
Ref HAL: hal-00647002_v1
DOI: 10.1063/1.3663072
WoS: 000297941100011
Exporter : BibTex | endNote
6 Citations
Résumé: We present a new optical arrangement which allows to avoid the broadening by finite aperture in Brillouin spectroscopy. In this system, all the rays scattered at the same angle by the whole scattering volume are collected on a single pixel of the area detector. This allows to use large collection angles, increasing the luminosity without lowering the accuracy of the frequency-shift and linewidth measurements. Several results of experimental checks are provided, showing the efficiency of the device.
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Dynamical origin of anomalous temperature hardening of elastic modulus in vitreous silica
Auteur(s): Ayrinhac Simon, Ruffle B., Foret M., Tran Trung Hieu, Clement S., Vialla R., Vacher R., Chervin Jean-Claude, Munsch Pascal, Polian Alain
(Article) Publié:
-Physical Review B Condensed Matter And Materials Physics (1998-2015), vol. 84 p.024201 (2011)
Ref HAL: hal-00607813_v1
DOI: 10.1103/PhysRevB.84.024201
WoS: 000292384100007
Exporter : BibTex | endNote
11 Citations
Résumé: High-resolution Brillouin scattering experiments are performed under hydrostatic pressures ranging from 0 to 10 GPa in vitreous silica. The hypersound-attenuation coefficient exhibits a sharp maximum located at 2 GPa, which appears to coincide with the well-known minimum in sound velocity. Two main processes contribute to sound damping: the thermal relaxation of local defects and the anharmonic interactions with thermal vibrations. By analyzing the temperature dependence of the velocity and subtracting the changes produced by the above mechanisms, the unrelaxed velocity is found. It is constant at low temperatures and increases anomalously above a temperature onset.We show that the onset strongly depends on pressure, which is in agreement with a dynamical origin of the structural changes that produce the hardening.
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Comment on "Visualizing coherent phonon propagation in the 100 GHz range: A broadband picosecond acoustic approach"
Auteur(s): Courtens E., Ruffle B., Foret M., Vacher R., Devos Arnaud
(Article) Publié:
Applied Physics Letters, vol. 98 p.246101 (2011)
Texte intégral en Openaccess : 
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Subterahertz hypersound attenuation in silica glass studied via picosecond acoustics
Auteur(s): Ayrinhac Simon, Foret M. , Devos Arnaud, Ruffle B., Courtens E., Vacher R.
(Article) Publié:
-Physical Review B Condensed Matter And Materials Physics (1998-2015), vol. 83 p.014204 (2011)
Texte intégral en Openaccess :
Ref HAL: hal-00567412_v1
DOI: 10.1103/PhysRevB.83.014204
WoS: 000286741100001
Exporter : BibTex | endNote
32 Citations
Résumé: We report picosecond acoustic measurements in silica-glass films grown by wet thermal oxidation on a (111) silicon substrate. The longitudinal acoustic phonons are observed over the range from 150 to 300 GHz using an infrared pump and a second harmonic blue probe. The transducer is an aluminum thin film deposited on top. Multiple interference effects are analyzed and fully taken into account. They lead to a signal presenting rapid oscillations as a function of the sample thicknesses. The latter are determined by separate interferometry. Our remarkably precise acoustic attenuation results are found to follow rather well a model combining thermally activated relaxations and anharmonicity. New values for the optical absorption of silicon in the 400-to-500-nm region of the spectrum are obtained as a by-product.
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Hyper-Raman Scattering: A Powerful Tool To Probe The Structure In Glasses
Auteur(s): Simon Guilhem, Hehlen B., Vacher R., Courtens E.
Conference: XXII International Conference on Raman Spectroscopy (Boston, MA, FR, 2010-08-08)
Actes de conférence: XXII International Conference on Raman Spectroscopy, vol. 1267 p.535-536 (2010)
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The boson peak of silica and its relation with elastic properties
Auteur(s): Ruffle B., Ayrinhac Simon, Courtens E., Vacher R., Foret M., Buchenau Uli, Wischnewski Andreas
Conference: XII International Workshop on Complex Systems (Andalo, IT, 2010-03-15)
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Damping of acoustic vibrations in silica glass
Auteur(s): Foret M., Ruffle B., Courtens E., Vacher R., Devos Arnaud, Ayrinhac Simon
Conference: XII International Workshop on Complex Systems (Andalo, IT, 2010-03-15)
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