Subterahertz hypersound attenuation in silica glass studied via picosecond acoustics

Article

关键词: VITREOUS SILICA;    THERMAL-CONDUCTIVITY;    BRILLOUIN-SCATTERING;    LOW-TEMPERATURES;    PHONONS;    RELAXATION;    MODES;    LIGHT;   

DOI  :  10.1103/PhysRevB.83.014204

来源: SCIE

【 摘 要 】

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.

【 授权许可】

Free