Laboratoire Charles Coulomb UMR 5221 CNRS/UM2 (L2C)


Accueil > La Recherche > Axes & Equipes > Matière Molle & Verres > Equipe : Physique des Verres > Thème : Structure, vibration, relaxations dans les systèmes désordonnés

Hypersound damping in vitreous silica measured by a picosecond optical technique

par sinfo - publié le , mis à jour le

Involved researchers : M. Foret, S. Ayrinhac (PhD), B. Rufflé

(Collaboration A. Devos, IEMN, Université Lille)

The attenuation of longitudinal acoustic phonons up to frequencies nearing 250 GHz is measured in vitreous silica with a picosecond optical technique. Taking advantage of interferences on the probe beam, difficulties encountered in early pioneering experiments are alleviated. Sound damping at 250 GHz and room temperature is consistent with relaxation dominated by anharmonic interactions with the thermal bath, extending optical Brillouin scattering data. Our result is at variance with claims of a recent deep-UV experiment which reported a rapid damping increase beyond 100 GHz. A comprehensive picture of the frequency dependence of sound attenuation in v-SiO2 can be proposed.

© L2C

Full widths of the Brillouin peaks deduced from different spectroscopies. The blue and magenta symbols are from Brillouin light scattering (BLS) experiments in the visible and the near-UV wavelength ranges, respectively. The open square is the lowest accessible inelastic x-ray scattering (IXS) point. Our POT results are shown as red points. The full line is the estimated sum of thermally activated relaxations and anharmonicity contributions, whereas the dot-dashed line is the expected Ω4 contribution.

A. Devos, M. Foret, S. Ayrinhac, P. Emery, and B. Rufflé, Hypersound damping in vitreous silica measured by picosecond ultrasonics, Phys. Rev. B 77 100201(R) (2008)