Photoacoustic response of a transmission photoacoustic configuration for two-layer samples with thermal memory

Abstract

In this paper, the models of surface temperature variations have been derived. Based on these models, photoacoustic (PA) response has been commented for transmission PA setup configurations of two-layer optically transparent samples, including the impact of finite heat propagation velocity through both layers (thermal memory) and the existence of volume absorption in both layers. By analyzing the derived model it has been shown that many parameters influence the photoacoustic response. Based on the derived model, some approximations have been discussed in order to enable the development of more accurate inverse solutions of photoacoustic problem, and the estimation of optical, thermal and other related physical properties of versatile materials. By using specific two-layer structure that consist of aluminum sample coated with layer of color dye, used in some photoacoustic experimental investigations, the influence of thermal memory properties of either the sample or the coating has been discussed.