How to Use Sound as a Powerful Tool for New Materials Characterization

This article will cover the fundamentals of solid-state photoacoustics, which involves sound wave generation by the sample illuminated with a modulated light source, and various sound applications within the characterization of the sample in the solid phase. Among the many sound components, the thermoelastic component is beneficial for establishing a generalized model to characterize the solid. Based on electro-acoustic analogies, the simplest analysis of the thermoelastic component in the frequency domain gives a relationship between the characteristic cut-off frequency of the mentioned component and the corresponding thickness of the investigated sample. The proportionality coefficient in this relationship represents the thermal diffusion coefficient for the sample material. This simple relation can be established for any material in the solid phase, allowing one to establish the generalized method aimed at material characterization. Such a method is reliable and precise and can be used in various branches of science and industry, from the analysis of new materials to material quality control in electrical and electronic engineering.