Advances in photothermal depth profiling

Abstract

Photothermal depth profiling is usually applied to inhomogeneous materials, and allows to localize the optical inhomogeneity or retrieve the thermal effusivity depth profile by simple monitoring the surface temperature or any related photothermal signal after the pump beam pulse absorption. In this article we want to discuss two different kind of inverse problems; the heat source depth profiling (1 st type), and the effusivity depth profiling (2 nd type). Finally we want to show the equivalence of the two problems, and provide some mathematical tools to get the solutions by the Thermal Wave Backscattering (TWBS).