Attenuation of Rayleigh Surface Waves in a Porous Material

Using acoustic microscopy at higher frequency, we show the velocity evolutions of surface acoustic waves, in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer. The velocities are obtained from different V(z) curves, which are determined experimentally at a frequency of 600 MHz. The analysis of V(z) data yields attenuation that is directly dependent on porosity. On the other hand, α_N attenuation has been modeled and allows us to investigate its influence on the velocity V_R of the propagation for Rayleigh waves.