Photothermoacoustic conversion in porous matrix-liquid filler systems

Features of the photothermoacoustic conversion in systems of the porous silicon-liquid filler type on a single crystal silicon substrate have been experimentally studied. It is established that the presence of liquid in the pores leads to a significant increase in the photoacoustic signal amplitude and front slope, which is explained by a significant contribution of the liquid pressure to thermoinduced stresses in the material. The extrema observed in time series of the photoacoustic signal in the case of a low-viscosity liquid are related to the process of pressure relaxation in the pores.