Acoustic phenomena in filled porous glasses by time-resolved spectroscopy
European Lab. for Non-Linear Spectroscopy (LENS), Univ. di Firenze, via N. Carrara 1, 50019 Sesto Fiorentino, Firenze, Italy
2 INFM-CRS-Soft Matter (CNR), c/o Univ. la Sapienza, Piaz. A. Moro 2, 00185 Roma, Italy
3 Dip. di Fisica, Univ. di Firenze, via Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
We studied the propagation of ultrasonic acoustic waves in two porous glasses characterized by different pore diameters (4 and 200 nm) filled with carbon tetrachloride. Using a time-resolved optical spectroscopic technique (Transient Grating) we can measure the acoustic dynamics of these systems. The sound velocities, measured in both the samples, show high values compared with the sound velocity of bulk carbon tetrachloride; they cannot be predicted by the simple effective medium model, but are in good agreement with the estimate obtained from the Biot theory.
© EDP Sciences, Springer-Verlag, 2007